diff --git a/sites/svelte-5-preview/src/lib/CodeMirror.svelte b/sites/svelte-5-preview/src/lib/CodeMirror.svelte
index f926d32f96..6ec16356e5 100644
--- a/sites/svelte-5-preview/src/lib/CodeMirror.svelte
+++ b/sites/svelte-5-preview/src/lib/CodeMirror.svelte
@@ -12,9 +12,6 @@
 	import Message from './Message.svelte';
 	import { svelteTheme } from './theme.js';
 
-	/** @type {import('./types').StartOrEnd | null} */
-	export let errorLoc = null;
-
 	/** @type {import('@codemirror/lint').LintSource | undefined} */
 	export let diagnostics = undefined;
 
@@ -171,9 +168,6 @@
 
 	let marked = false;
 
-	/** @type {number | null}*/
-	let error_line = null;
-
 	let updating_externally = false;
 
 	/** @type {import('@codemirror/state').Extension[]} */
@@ -181,27 +175,15 @@
 
 	let cursor_pos = 0;
 
-	$: {
-		if ($cmInstance.view) {
-			fulfil_module_editor_ready();
-		}
+	$: if ($cmInstance.view) {
+		fulfil_module_editor_ready();
 	}
 
 	$: if ($cmInstance.view && w && h) resize();
 
-	$: {
-		if (marked) {
-			unmarkText();
-			marked = false;
-		}
-
-		if (errorLoc) {
-			markText({ from: errorLoc.character, to: errorLoc.character + 1, className: 'error-loc' });
-
-			error_line = errorLoc.line;
-		} else {
-			error_line = null;
-		}
+	$: if (marked) {
+		unmarkText();
+		marked = false;
 	}
 
 	const watcher = EditorView.updateListener.of((viewUpdate) => {
diff --git a/sites/svelte-5-preview/src/lib/Input/ModuleEditor.svelte b/sites/svelte-5-preview/src/lib/Input/ModuleEditor.svelte
index ded9816bd8..b182635350 100644
--- a/sites/svelte-5-preview/src/lib/Input/ModuleEditor.svelte
+++ b/sites/svelte-5-preview/src/lib/Input/ModuleEditor.svelte
@@ -3,9 +3,6 @@
 	import { get_full_filename } from '$lib/utils.js';
 	import CodeMirror from '../CodeMirror.svelte';
 
-	/** @type {import('$lib/types').StartOrEnd | null} */
-	export let errorLoc = null;
-
 	/** @type {boolean} */
 	export let autocomplete;
 
@@ -58,7 +55,6 @@
 	<div class="editor notranslate" translate="no">
 		<CodeMirror
 			bind:this={$module_editor}
-			{errorLoc}
 			{autocomplete}
 			diagnostics={$selected && $bundle ? diagnostics : () => []}
 			on:change={handle_change}
diff --git a/sites/svelte-5-preview/src/lib/Output/Output.svelte b/sites/svelte-5-preview/src/lib/Output/Output.svelte
index b3bdee8d89..3b6f371787 100644
--- a/sites/svelte-5-preview/src/lib/Output/Output.svelte
+++ b/sites/svelte-5-preview/src/lib/Output/Output.svelte
@@ -10,9 +10,6 @@
 	/** @type {string | null} */
 	export let status;
 
-	/** @type {import('$lib/types').StartOrEnd | null} */
-	export let sourceErrorLoc = null;
-
 	/** @type {import('$lib/types').MessageDetails | null} */
 	export let runtimeError = null;
 
@@ -97,11 +94,11 @@
 <!-- js output -->
 <div class="tab-content" class:visible={selected?.type !== 'md' && view === 'js'}>
 	{#if embedded}
-		<CodeMirror bind:this={js_editor} errorLoc={sourceErrorLoc} readonly />
+		<CodeMirror bind:this={js_editor} readonly />
 	{:else}
 		<PaneWithPanel pos="50%" panel="Compiler options">
 			<div slot="main">
-				<CodeMirror bind:this={js_editor} errorLoc={sourceErrorLoc} readonly />
+				<CodeMirror bind:this={js_editor} readonly />
 			</div>
 
 			<div slot="panel-body">
@@ -113,7 +110,7 @@
 
 <!-- css output -->
 <div class="tab-content" class:visible={selected?.type !== 'md' && view === 'css'}>
-	<CodeMirror bind:this={css_editor} errorLoc={sourceErrorLoc} readonly />
+	<CodeMirror bind:this={css_editor} readonly />
 </div>
 
 <!-- ast output -->
diff --git a/sites/svelte-5-preview/src/lib/Repl.svelte b/sites/svelte-5-preview/src/lib/Repl.svelte
index 67d927374e..5ab0390e49 100644
--- a/sites/svelte-5-preview/src/lib/Repl.svelte
+++ b/sites/svelte-5-preview/src/lib/Repl.svelte
@@ -260,8 +260,6 @@
 
 	$: $toggleable = mobile && orientation === 'columns';
 
-	/** @type {import('./types').StartOrEnd} */
-	let sourceErrorLoc;
 	let width = 0;
 	let show_output = false;
 
@@ -321,7 +319,7 @@
 		>
 			<section slot="a">
 				<ComponentSelector show_modified={showModified} on:add on:remove />
-				<ModuleEditor errorLoc={sourceErrorLoc} {autocomplete} />
+				<ModuleEditor {autocomplete} />
 			</section>
 
 			<section slot="b" style="height: 100%;">