diff --git a/documentation/docs/02-runes/04-$effect.md b/documentation/docs/02-runes/04-$effect.md
index 1ea960de70..da24084d4d 100644
--- a/documentation/docs/02-runes/04-$effect.md
+++ b/documentation/docs/02-runes/04-$effect.md
@@ -66,7 +66,7 @@ You can return a function from `$effect`, which will run immediately before the
 
 ### Understanding dependencies
 
-`$effect` automatically picks up any reactive values (`$state`, `$derived`, `$props`) that are _synchronously_ read inside its function body and registers them as dependencies. When those dependencies change, the `$effect` schedules a rerun.
+`$effect` automatically picks up any reactive values (`$state`, `$derived`, `$props`) that are _synchronously_ read inside its function body (including indirectly, via function calls) and registers them as dependencies. When those dependencies change, the `$effect` schedules a rerun.
 
 Values that are read _asynchronously_ — after an `await` or inside a `setTimeout`, for example — will not be tracked. Here, the canvas will be repainted when `color` changes, but not when `size` changes ([demo](/playground/untitled#H4sIAAAAAAAAE31T246bMBD9lZF3pWSlBEirfaEQqdo_2PatVIpjBrDkGGQPJGnEv1e2IZfVal-wfHzmzJyZ4cIqqdCy9M-F0blDlnqArZjmB3f72XWRHVCRw_bc4me4aDWhJstSlllhZEfbQhekkMDKfwg5PFvihMvX5OXH_CJa1Zrb0-Kpqr5jkiwC48rieuDWQbqgZ6wqFLRcvkC-hYvnkWi1dWqa8ESQTxFRjfQWsOXiWzmr0sSLhEJu3p1YsoJkNUcdZUnN9dagrBu6FVRQHAM10sJRKgUG16bXcGxQ44AGdt7SDkTDdY02iqLHnJVU6hedlWuIp94JW6Tf8oBt_8GdTxlF0b4n0C35ZLBzXb3mmYn3ae6cOW74zj0YVzDNYXRHFt9mprNgHfZSl6mzml8CMoLvTV6wTZIUDEJv5us2iwMtiJRyAKG4tXnhl8O0yhbML0Wm-B7VNlSSSd31BG7z8oIZZ6dgIffAVY_5xdU9Qrz1Bnx8fCfwtZ7v8Qc9j3nB8PqgmMWlHIID6-bkVaPZwDySfWtKNGtquxQ23Qlsq2QJT0KIqb8dL0up6xQ2eIBkAg_c1FI_YqW0neLnFCqFpwmreedJYT7XX8FVOBfwWRhXstZrSXiwKQjUhOZeMIleb5JZfHWn2Yq5pWEpmR7Hv-N_wEqT8hEEAAA=)):
 
diff --git a/documentation/docs/03-template-syntax/09-@const.md b/documentation/docs/03-template-syntax/09-@const.md
index c42d3560fd..2a587b7a3d 100644
--- a/documentation/docs/03-template-syntax/09-@const.md
+++ b/documentation/docs/03-template-syntax/09-@const.md
@@ -11,4 +11,4 @@ The `{@const ...}` tag defines a local constant.
 {/each}
 ```
 
-`{@const}` is only allowed as an immediate child of a block — `{#if ...}`, `{#each ...}`, `{#snippet ...}` and so on — a `<Component />` or a `<svelte:boundary`.
+`{@const}` is only allowed as an immediate child of a block — `{#if ...}`, `{#each ...}`, `{#snippet ...}` and so on — a `<Component />` or a `<svelte:boundary>`.
diff --git a/documentation/docs/03-template-syntax/11-bind.md b/documentation/docs/03-template-syntax/11-bind.md
index 90046c8c45..e56c2b4f77 100644
--- a/documentation/docs/03-template-syntax/11-bind.md
+++ b/documentation/docs/03-template-syntax/11-bind.md
@@ -235,7 +235,7 @@ You can give the `<select>` a default value by adding a `selected` attribute to
 
 ## `<video>`
 
-`<video>` elements have all the same bindings as [#audio] elements, plus readonly [`videoWidth`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLVideoElement/videoWidth) and [`videoHeight`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLVideoElement/videoHeight) bindings.
+`<video>` elements have all the same bindings as [`<audio>`](#audio) elements, plus readonly [`videoWidth`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLVideoElement/videoWidth) and [`videoHeight`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLVideoElement/videoHeight) bindings.
 
 ## `<img>`
 
diff --git a/documentation/docs/04-styling/01-scoped-styles.md b/documentation/docs/04-styling/01-scoped-styles.md
index f870d0a5b8..eae26d0cb1 100644
--- a/documentation/docs/04-styling/01-scoped-styles.md
+++ b/documentation/docs/04-styling/01-scoped-styles.md
@@ -33,10 +33,7 @@ If a component defines `@keyframes`, the name is scoped to the component using t
 
 	/* these keyframes are only accessible inside this component */
 	@keyframes bounce {
-		/* ... *.
+		/* ... */
 	}
 </style>
 ```
-
-
-
diff --git a/documentation/docs/05-special-elements/01-svelte-boundary.md b/documentation/docs/05-special-elements/01-svelte-boundary.md
index 15f249a771..f5439b4b83 100644
--- a/documentation/docs/05-special-elements/01-svelte-boundary.md
+++ b/documentation/docs/05-special-elements/01-svelte-boundary.md
@@ -13,7 +13,7 @@ Boundaries allow you to guard against errors in part of your app from breaking t
 
 If an error occurs while rendering or updating the children of a `<svelte:boundary>`, or running any [`$effect`]($effect) functions contained therein, the contents will be removed.
 
-Errors occurring outside the rendering process (for example, in event handlers) are _not_ caught by error boundaries.
+Errors occurring outside the rendering process (for example, in event handlers or after a `setTimeout` or async work) are _not_ caught by error boundaries.
 
 ## Properties
 
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index bb48391e0e..0e8073cc5d 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,21 @@
 # svelte
 
+## 5.19.6
+
+### Patch Changes
+
+- fix: do not prune selectors like `:global(.foo):has(.scoped)` ([#15140](https://github.com/sveltejs/svelte/pull/15140))
+
+- fix: don't error on slot prop inside block inside other component ([#15148](https://github.com/sveltejs/svelte/pull/15148))
+
+- fix: ensure reactions are correctly attached for unowned deriveds ([#15158](https://github.com/sveltejs/svelte/pull/15158))
+
+- fix: silence a11y attribute warnings when spread attributes present ([#15150](https://github.com/sveltejs/svelte/pull/15150))
+
+- fix: prevent false-positive ownership validations due to hot reload ([#15154](https://github.com/sveltejs/svelte/pull/15154))
+
+- fix: widen ownership when calling setContext ([#15153](https://github.com/sveltejs/svelte/pull/15153))
+
 ## 5.19.5
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a44ba43364..a286fa119d 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.19.5",
+  "version": "5.19.6",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
index 109010e88c..e719895798 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
@@ -339,13 +339,18 @@ function relative_selector_might_apply_to_node(relative_selector, rule, element)
 		let sibling_elements; // do them lazy because it's rarely used and expensive to calculate
 
 		// If this is a :has inside a global selector, we gotta include the element itself, too,
-		// because the global selector might be for an element that's outside the component (e.g. :root).
+		// because the global selector might be for an element that's outside the component,
+		// e.g. :root:has(.scoped), :global(.foo):has(.scoped), or :root { &:has(.scoped) {} }
 		const rules = get_parent_rules(rule);
 		const include_self =
 			rules.some((r) => r.prelude.children.some((c) => c.children.some((s) => is_global(s, r)))) ||
 			rules[rules.length - 1].prelude.children.some((c) =>
 				c.children.some((r) =>
-					r.selectors.some((s) => s.type === 'PseudoClassSelector' && s.name === 'root')
+					r.selectors.some(
+						(s) =>
+							s.type === 'PseudoClassSelector' &&
+							(s.name === 'root' || (s.name === 'global' && s.args))
+					)
 				)
 			);
 		if (include_self) {
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y.js
index a5ca8463a4..24a8e5122d 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y.js
@@ -756,7 +756,8 @@ export function check_element(node, context) {
 				name === 'aria-activedescendant' &&
 				!is_dynamic_element &&
 				!is_interactive_element(node.name, attribute_map) &&
-				!attribute_map.has('tabindex')
+				!attribute_map.has('tabindex') &&
+				!has_spread
 			) {
 				w.a11y_aria_activedescendant_has_tabindex(attribute);
 			}
@@ -810,9 +811,9 @@ export function check_element(node, context) {
 						const role = roles_map.get(current_role);
 						if (role) {
 							const required_role_props = Object.keys(role.requiredProps);
-							const has_missing_props = required_role_props.some(
-								(prop) => !attributes.find((a) => a.name === prop)
-							);
+							const has_missing_props =
+								!has_spread &&
+								required_role_props.some((prop) => !attributes.find((a) => a.name === prop));
 							if (has_missing_props) {
 								w.a11y_role_has_required_aria_props(
 									attribute,
@@ -828,6 +829,7 @@ export function check_element(node, context) {
 
 					// interactive-supports-focus
 					if (
+						!has_spread &&
 						!has_disabled_attribute(attribute_map) &&
 						!is_hidden_from_screen_reader(node.name, attribute_map) &&
 						!is_presentation_role(current_role) &&
@@ -845,6 +847,7 @@ export function check_element(node, context) {
 
 					// no-interactive-element-to-noninteractive-role
 					if (
+						!has_spread &&
 						is_interactive_element(node.name, attribute_map) &&
 						(is_non_interactive_roles(current_role) || is_presentation_role(current_role))
 					) {
@@ -853,6 +856,7 @@ export function check_element(node, context) {
 
 					// no-noninteractive-element-to-interactive-role
 					if (
+						!has_spread &&
 						is_non_interactive_element(node.name, attribute_map) &&
 						is_interactive_roles(current_role) &&
 						!a11y_non_interactive_element_to_interactive_role_exceptions[node.name]?.includes(
@@ -947,6 +951,7 @@ export function check_element(node, context) {
 
 	// no-noninteractive-element-interactions
 	if (
+		!has_spread &&
 		!has_contenteditable_attr &&
 		!is_hidden_from_screen_reader(node.name, attribute_map) &&
 		!is_presentation_role(role_static_value) &&
@@ -964,6 +969,7 @@ export function check_element(node, context) {
 
 	// no-static-element-interactions
 	if (
+		!has_spread &&
 		(!role || role_static_value !== null) &&
 		!is_hidden_from_screen_reader(node.name, attribute_map) &&
 		!is_presentation_role(role_static_value) &&
@@ -981,11 +987,11 @@ export function check_element(node, context) {
 		}
 	}
 
-	if (handlers.has('mouseover') && !handlers.has('focus')) {
+	if (!has_spread && handlers.has('mouseover') && !handlers.has('focus')) {
 		w.a11y_mouse_events_have_key_events(node, 'mouseover', 'focus');
 	}
 
-	if (handlers.has('mouseout') && !handlers.has('blur')) {
+	if (!has_spread && handlers.has('mouseout') && !handlers.has('blur')) {
 		w.a11y_mouse_events_have_key_events(node, 'mouseout', 'blur');
 	}
 
@@ -995,7 +1001,7 @@ export function check_element(node, context) {
 	if (node.name === 'a' || node.name === 'button') {
 		const is_hidden = get_static_value(attribute_map.get('aria-hidden')) === 'true';
 
-		if (!is_hidden && !is_labelled && !has_content(node)) {
+		if (!has_spread && !is_hidden && !is_labelled && !has_content(node)) {
 			w.a11y_consider_explicit_label(node);
 		}
 	}
@@ -1054,7 +1060,7 @@ export function check_element(node, context) {
 	if (node.name === 'img') {
 		const alt_attribute = get_static_text_value(attribute_map.get('alt'));
 		const aria_hidden = get_static_value(attribute_map.get('aria-hidden'));
-		if (alt_attribute && !aria_hidden) {
+		if (alt_attribute && !aria_hidden && !has_spread) {
 			if (/\b(image|picture|photo)\b/i.test(alt_attribute)) {
 				w.a11y_img_redundant_alt(node);
 			}
@@ -1087,7 +1093,7 @@ export function check_element(node, context) {
 			);
 			return has;
 		};
-		if (!attribute_map.has('for') && !has_input_child(node)) {
+		if (!has_spread && !attribute_map.has('for') && !has_input_child(node)) {
 			w.a11y_label_has_associated_control(node);
 		}
 	}
@@ -1095,7 +1101,7 @@ export function check_element(node, context) {
 	if (node.name === 'video') {
 		const aria_hidden_attribute = attribute_map.get('aria-hidden');
 		const aria_hidden_exist = aria_hidden_attribute && get_static_value(aria_hidden_attribute);
-		if (attribute_map.has('muted') || aria_hidden_exist === 'true') {
+		if (attribute_map.has('muted') || aria_hidden_exist === 'true' || has_spread) {
 			return;
 		}
 		let has_caption = false;
@@ -1141,6 +1147,7 @@ export function check_element(node, context) {
 
 	// Check content
 	if (
+		!has_spread &&
 		!is_labelled &&
 		!has_contenteditable_binding &&
 		a11y_required_content.includes(node.name) &&
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/attribute.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/attribute.js
index 198e464ac7..19bd7b6e54 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/attribute.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/attribute.js
@@ -80,40 +80,42 @@ export function validate_slot_attribute(context, attribute, is_component = false
 	}
 
 	if (owner) {
-		if (!is_text_attribute(attribute)) {
-			e.slot_attribute_invalid(attribute);
-		}
-
 		if (
 			owner.type === 'Component' ||
 			owner.type === 'SvelteComponent' ||
 			owner.type === 'SvelteSelf'
 		) {
 			if (owner !== parent) {
-				e.slot_attribute_invalid_placement(attribute);
-			}
+				if (!is_component) {
+					e.slot_attribute_invalid_placement(attribute);
+				}
+			} else {
+				if (!is_text_attribute(attribute)) {
+					e.slot_attribute_invalid(attribute);
+				}
 
-			const name = attribute.value[0].data;
+				const name = attribute.value[0].data;
 
-			if (context.state.component_slots.has(name)) {
-				e.slot_attribute_duplicate(attribute, name, owner.name);
-			}
-
-			context.state.component_slots.add(name);
+				if (context.state.component_slots.has(name)) {
+					e.slot_attribute_duplicate(attribute, name, owner.name);
+				}
 
-			if (name === 'default') {
-				for (const node of owner.fragment.nodes) {
-					if (node.type === 'Text' && regex_only_whitespaces.test(node.data)) {
-						continue;
-					}
+				context.state.component_slots.add(name);
 
-					if (node.type === 'RegularElement' || node.type === 'SvelteFragment') {
-						if (node.attributes.some((a) => a.type === 'Attribute' && a.name === 'slot')) {
+				if (name === 'default') {
+					for (const node of owner.fragment.nodes) {
+						if (node.type === 'Text' && regex_only_whitespaces.test(node.data)) {
 							continue;
 						}
-					}
 
-					e.slot_default_duplicate(node);
+						if (node.type === 'RegularElement' || node.type === 'SvelteFragment') {
+							if (node.attributes.some((a) => a.type === 'Attribute' && a.name === 'slot')) {
+								continue;
+							}
+						}
+
+						e.slot_default_duplicate(node);
+					}
 				}
 			}
 		}
diff --git a/packages/svelte/src/internal/client/context.js b/packages/svelte/src/internal/client/context.js
index e1088edf30..bd94d5ad8a 100644
--- a/packages/svelte/src/internal/client/context.js
+++ b/packages/svelte/src/internal/client/context.js
@@ -8,7 +8,8 @@ import {
 	active_effect,
 	active_reaction,
 	set_active_effect,
-	set_active_reaction
+	set_active_reaction,
+	untrack
 } from './runtime.js';
 import { effect } from './reactivity/effects.js';
 import { legacy_mode_flag } from '../flags/index.js';
@@ -49,14 +50,6 @@ export function set_dev_current_component_function(fn) {
 export function getContext(key) {
 	const context_map = get_or_init_context_map('getContext');
 	const result = /** @type {T} */ (context_map.get(key));
-
-	if (DEV) {
-		const fn = /** @type {ComponentContext} */ (component_context).function;
-		if (fn) {
-			add_owner(result, fn, true);
-		}
-	}
-
 	return result;
 }
 
@@ -74,6 +67,15 @@ export function getContext(key) {
  */
 export function setContext(key, context) {
 	const context_map = get_or_init_context_map('setContext');
+
+	if (DEV) {
+		// When state is put into context, we treat as if it's global from now on.
+		// We do for performance reasons (it's for example very expensive to call
+		// getContext on a big object many times when part of a list component)
+		// and danger of false positives.
+		untrack(() => add_owner(context, null, true));
+	}
+
 	context_map.set(key, context);
 	return context;
 }
@@ -100,16 +102,6 @@ export function hasContext(key) {
  */
 export function getAllContexts() {
 	const context_map = get_or_init_context_map('getAllContexts');
-
-	if (DEV) {
-		const fn = component_context?.function;
-		if (fn) {
-			for (const value of context_map.values()) {
-				add_owner(value, fn, true);
-			}
-		}
-	}
-
 	return /** @type {T} */ (context_map);
 }
 
diff --git a/packages/svelte/src/internal/client/dev/ownership.js b/packages/svelte/src/internal/client/dev/ownership.js
index 70cfbb47f3..2a2527803a 100644
--- a/packages/svelte/src/internal/client/dev/ownership.js
+++ b/packages/svelte/src/internal/client/dev/ownership.js
@@ -109,7 +109,7 @@ export function mark_module_end(component) {
 
 /**
  * @param {any} object
- * @param {any} owner
+ * @param {any | null} owner
  * @param {boolean} [global]
  * @param {boolean} [skip_warning]
  */
@@ -120,7 +120,7 @@ export function add_owner(object, owner, global = false, skip_warning = false) {
 		if (metadata && !has_owner(metadata, component)) {
 			let original = get_owner(metadata);
 
-			if (owner[FILENAME] !== component[FILENAME] && !skip_warning) {
+			if (owner && owner[FILENAME] !== component[FILENAME] && !skip_warning) {
 				w.ownership_invalid_binding(component[FILENAME], owner[FILENAME], original[FILENAME]);
 			}
 		}
@@ -165,7 +165,7 @@ export function widen_ownership(from, to) {
 
 /**
  * @param {any} object
- * @param {Function} owner
+ * @param {Function | null} owner If `null`, then the object is globally owned and will not be checked
  * @param {Set<any>} seen
  */
 function add_owner_to_object(object, owner, seen) {
@@ -174,7 +174,11 @@ function add_owner_to_object(object, owner, seen) {
 	if (metadata) {
 		// this is a state proxy, add owner directly, if not globally shared
 		if ('owners' in metadata && metadata.owners != null) {
-			metadata.owners.add(owner);
+			if (owner) {
+				metadata.owners.add(owner);
+			} else {
+				metadata.owners = null;
+			}
 		}
 	} else if (object && typeof object === 'object') {
 		if (seen.has(object)) return;
@@ -216,6 +220,10 @@ function has_owner(metadata, component) {
 
 	return (
 		metadata.owners.has(component) ||
+		// This helps avoid false positives when using HMR, where the component function is replaced
+		[...metadata.owners].some(
+			(owner) => /** @type {any} */ (owner)[FILENAME] === /** @type {any} */ (component)?.[FILENAME]
+		) ||
 		(metadata.parent !== null && has_owner(metadata.parent, component))
 	);
 }
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 135aa5e2bf..3d838e19bb 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -320,7 +320,7 @@ export function suspend() {
 
 	return function unsuspend() {
 		// @ts-ignore
-		boundary?.fn(ASYNC_DECREMENT);
+		boundary?.fn?.(ASYNC_DECREMENT);
 	};
 }
 
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 040e585215..3baa03a917 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -219,17 +219,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 		}
 
 		if (!hydrating) {
-			var effect = /** @type {Effect} */ (active_reaction);
-			reconcile(
-				array,
-				state,
-				anchor,
-				render_fn,
-				flags,
-				(effect.f & INERT) !== 0,
-				get_key,
-				get_collection
-			);
+			reconcile(array, state, anchor, render_fn, flags, get_key, get_collection);
 		}
 
 		if (fallback_fn !== null) {
@@ -273,12 +263,11 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
  * @param {Element | Comment | Text} anchor
  * @param {(anchor: Node, item: MaybeSource<V>, index: number | Source<number>, collection: () => V[]) => void} render_fn
  * @param {number} flags
- * @param {boolean} is_inert
  * @param {(value: V, index: number) => any} get_key
  * @param {() => V[]} get_collection
  * @returns {void}
  */
-function reconcile(array, state, anchor, render_fn, flags, is_inert, get_key, get_collection) {
+function reconcile(array, state, anchor, render_fn, flags, get_key, get_collection) {
 	var is_animated = (flags & EACH_IS_ANIMATED) !== 0;
 	var should_update = (flags & (EACH_ITEM_REACTIVE | EACH_INDEX_REACTIVE)) !== 0;
 
@@ -420,7 +409,7 @@ function reconcile(array, state, anchor, render_fn, flags, is_inert, get_key, ge
 			while (current !== null && current.k !== key) {
 				// If the each block isn't inert and an item has an effect that is already inert,
 				// skip over adding it to our seen Set as the item is already being handled
-				if (is_inert || (current.e.f & INERT) === 0) {
+				if ((current.e.f & INERT) === 0) {
 					(seen ??= new Set()).add(current);
 				}
 				stashed.push(current);
@@ -444,7 +433,7 @@ function reconcile(array, state, anchor, render_fn, flags, is_inert, get_key, ge
 
 		while (current !== null) {
 			// If the each block isn't inert, then inert effects are currently outroing and will be removed once the transition is finished
-			if (is_inert || (current.e.f & INERT) === 0) {
+			if ((current.e.f & INERT) === 0) {
 				to_destroy.push(current);
 			}
 			current = current.next;
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 8df9d31440..2fdcc4f048 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -838,12 +838,19 @@ function process_effects(effect, collected_effects) {
 						current_effect.f ^= CLEAN;
 					}
 				} else if (!skip_suspended) {
+					// Ensure we set the effect to be the active reaction
+					// to ensure that unowned deriveds are correctly tracked
+					// because we're flushing the current effect
+					var previous_active_reaction = active_reaction;
 					try {
+						active_reaction = current_effect;
 						if (check_dirtiness(current_effect)) {
 							update_effect(current_effect);
 						}
 					} catch (error) {
 						handle_error(error, current_effect, null, current_effect.ctx);
+					} finally {
+						active_reaction = previous_active_reaction;
 					}
 				}
 
@@ -1022,13 +1029,11 @@ export function get(signal) {
 		var derived = /** @type {Derived} */ (signal);
 		var parent = derived.parent;
 
-		if (parent !== null) {
+		if (parent !== null && (parent.f & UNOWNED) === 0) {
 			// If the derived is owned by another derived then mark it as unowned
 			// as the derived value might have been referenced in a different context
 			// since and thus its parent might not be its true owner anymore
-			if ((parent.f & UNOWNED) === 0) {
-				derived.f ^= UNOWNED;
-			}
+			derived.f ^= UNOWNED;
 		}
 	}
 
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index a509ef3fec..03ab37b583 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.19.5';
+export const VERSION = '5.19.6';
 export const PUBLIC_VERSION = '5';
diff --git a/packages/svelte/tests/css/samples/has/_config.js b/packages/svelte/tests/css/samples/has/_config.js
index 33bbe74949..8d89d98cbd 100644
--- a/packages/svelte/tests/css/samples/has/_config.js
+++ b/packages/svelte/tests/css/samples/has/_config.js
@@ -197,6 +197,20 @@ export default test({
 				column: 16,
 				character: 1614
 			}
+		},
+		{
+			code: 'css_unused_selector',
+			message: 'Unused CSS selector ":global(.foo):has(.unused)"',
+			start: {
+				line: 155,
+				column: 1,
+				character: 1684
+			},
+			end: {
+				line: 155,
+				column: 27,
+				character: 1710
+			}
 		}
 	]
 });
diff --git a/packages/svelte/tests/css/samples/has/expected.css b/packages/svelte/tests/css/samples/has/expected.css
index 9627bf730c..b257370d61 100644
--- a/packages/svelte/tests/css/samples/has/expected.css
+++ b/packages/svelte/tests/css/samples/has/expected.css
@@ -136,3 +136,10 @@
 			color: red;
 		}*/
 	}
+
+	.foo:has(x.svelte-xyz) {
+		color: green;
+	}
+	/* (unused) :global(.foo):has(.unused) {
+		color: red;
+	}*/
diff --git a/packages/svelte/tests/css/samples/has/input.svelte b/packages/svelte/tests/css/samples/has/input.svelte
index 946cf2df90..9b254996bf 100644
--- a/packages/svelte/tests/css/samples/has/input.svelte
+++ b/packages/svelte/tests/css/samples/has/input.svelte
@@ -148,4 +148,11 @@
 			color: red;
 		}
 	}
+
+	:global(.foo):has(x) {
+		color: green;
+	}
+	:global(.foo):has(.unused) {
+		color: red;
+	}
 </style>
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child.svelte b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child.svelte
new file mode 100644
index 0000000000..cd215304a3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { value = $bindable() } = $props()
+</script>
+
+<button onclick={() => value = 'a'}>change</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child2.svelte b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child2.svelte
new file mode 100644
index 0000000000..a1d9f93bec
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/Child2.svelte
@@ -0,0 +1,5 @@
+<script>
+	let {disabled = false} = $props()
+</script>
+
+{disabled}
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/_config.js
new file mode 100644
index 0000000000..9948f91966
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/_config.js
@@ -0,0 +1,16 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		let [btn1, btn2] = target.querySelectorAll('button');
+
+		btn1?.click();
+		flushSync();
+
+		btn2?.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<button>change</button><button>change</button>\nfalse`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/main.svelte
new file mode 100644
index 0000000000..0219acdf7f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-unowned-11/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child2 from './Child2.svelte'
+	import Child from './Child.svelte'
+	let loginname = $state('')
+	let password = $state('')
+</script>
+
+<Child bind:value={loginname} />
+<Child bind:value={password} />
+<Child2 disabled={!loginname || !password} />
+
diff --git a/packages/svelte/tests/validator/samples/a11y-label-has-associated-control/input.svelte b/packages/svelte/tests/validator/samples/a11y-label-has-associated-control/input.svelte
index 124888c089..f47743b33b 100644
--- a/packages/svelte/tests/validator/samples/a11y-label-has-associated-control/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-label-has-associated-control/input.svelte
@@ -10,3 +10,4 @@
 <label>E <span></span></label>
 <label>F {#if true}<input type="text" />{/if}</label>
 <LabelComponent>G <input type="text" /></LabelComponent>
+<label {...forMightBeInHere}>E <span></span></label>
\ No newline at end of file
diff --git a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
index 613b80e6d9..f9fe4f15c1 100644
--- a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
@@ -1,21 +1,19 @@
 <script>
-	// Even if otherProps contains onBlur and/or onFocus, the rule will still fail.
-	// Props should be passed down explicitly for rule to pass.
 	const otherProps = {
-		onBlur: () => void 0,
-		onFocus: () => void 0
+		onblur: () => {},
+		onfocus: () => {}
 	};
 </script>
 
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseover={() => void 0}></div>
+<div onmouseover={() => {}}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseover={() => void 0} on:focus={() => void 0}></div>
+<div onmouseover={() => {}} onfocus={() => {}}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseover={() => void 0} {...otherProps}></div>
+<div onmouseover={() => {}} {...otherProps}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseout={() => void 0}></div>
+<div onmouseout={() => {}}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseout={() => void 0} on:blur={() => void 0}></div>
+<div onmouseout={() => {}} onblur={() => {}}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div on:mouseout={() => void 0} {...otherProps}></div>
+<div onmouseout={() => {}} {...otherProps}></div>
diff --git a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/warnings.json b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/warnings.json
index 574b019e0f..3dee4e9673 100644
--- a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/warnings.json
+++ b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/warnings.json
@@ -2,49 +2,25 @@
 	{
 		"code": "a11y_mouse_events_have_key_events",
 		"end": {
-			"column": 39,
-			"line": 11
+			"column": 34,
+			"line": 9
 		},
 		"message": "'mouseover' event must be accompanied by 'focus' event",
 		"start": {
 			"column": 0,
-			"line": 11
+			"line": 9
 		}
 	},
 	{
 		"code": "a11y_mouse_events_have_key_events",
 		"end": {
-			"column": 55,
+			"column": 33,
 			"line": 15
 		},
-		"message": "'mouseover' event must be accompanied by 'focus' event",
-		"start": {
-			"column": 0,
-			"line": 15
-		}
-	},
-	{
-		"code": "a11y_mouse_events_have_key_events",
-		"end": {
-			"column": 38,
-			"line": 17
-		},
 		"message": "'mouseout' event must be accompanied by 'blur' event",
 		"start": {
 			"column": 0,
-			"line": 17
-		}
-	},
-	{
-		"code": "a11y_mouse_events_have_key_events",
-		"end": {
-			"column": 54,
-			"line": 21
-		},
-		"message": "'mouseout' event must be accompanied by 'blur' event",
-		"start": {
-			"column": 0,
-			"line": 21
+			"line": 15
 		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/slot-attribute-component/input.svelte b/packages/svelte/tests/validator/samples/slot-attribute-component/input.svelte
index 5acb14e409..5d559e614e 100644
--- a/packages/svelte/tests/validator/samples/slot-attribute-component/input.svelte
+++ b/packages/svelte/tests/validator/samples/slot-attribute-component/input.svelte
@@ -1,2 +1,8 @@
 <Foo slot="foo">valid</Foo>
 <Foo slot={foo}>valid</Foo>
+<Foo>
+    {#if true}
+        <Foo slot="foo">valid</Foo>
+        <Foo slot={foo}>valid</Foo>
+    {/if}
+</Foo>
\ No newline at end of file