diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index 9564307071..b0dca3dbe8 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -248,6 +248,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private SwitchCompat swThreadByRef;
     private SwitchCompat swMdn;
     private SwitchCompat swAppChooser;
+    private SwitchCompat swAdjacent;
     private SwitchCompat swDeleteConfirmation;
     private SwitchCompat swDmarcViewer;
     private EditText etKeywords;
@@ -313,7 +314,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             "exact_alarms",
             "native_dkim", "native_arc", "native_arc_whitelist",
             "webp", "easy_correct", "infra", "tld_flags", "dup_msgids", "thread_byref", "mdn",
-            "app_chooser", "delete_confirmation", "global_keywords", "test_iab"
+            "app_chooser", "adjacent", "delete_confirmation", "global_keywords", "test_iab"
     };
 
     private final static String[] RESET_QUESTIONS = new String[]{
@@ -510,6 +511,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swThreadByRef = view.findViewById(R.id.swThreadByRef);
         swMdn = view.findViewById(R.id.swMdn);
         swAppChooser = view.findViewById(R.id.swAppChooser);
+        swAdjacent = view.findViewById(R.id.swAdjacent);
         swDeleteConfirmation = view.findViewById(R.id.swDeleteConfirmation);
         swDmarcViewer = view.findViewById(R.id.swDmarcViewer);
         etKeywords = view.findViewById(R.id.etKeywords);
@@ -1942,6 +1944,13 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
+        swAdjacent.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("adjacent", checked).apply();
+            }
+        });
+
         swDeleteConfirmation.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -2724,6 +2733,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             swThreadByRef.setChecked(prefs.getBoolean("thread_byref", true));
             swMdn.setChecked(prefs.getBoolean("mdn", swExperiments.isChecked()));
             swAppChooser.setChecked(prefs.getBoolean("app_chooser", false));
+            swAdjacent.setChecked(prefs.getBoolean("adjacent", false));
             swDeleteConfirmation.setChecked(prefs.getBoolean("delete_confirmation", true));
             swDmarcViewer.setChecked(Helper.isComponentEnabled(getContext(), ActivityDmarc.class));
             etKeywords.setText(prefs.getString("global_keywords", null));
diff --git a/app/src/main/java/eu/faircode/email/Helper.java b/app/src/main/java/eu/faircode/email/Helper.java
index 6de910ef0a..9fa9c95d99 100644
--- a/app/src/main/java/eu/faircode/email/Helper.java
+++ b/app/src/main/java/eu/faircode/email/Helper.java
@@ -1008,6 +1008,14 @@ public class Helper {
         intent.setDataAndTypeAndNormalize(uri, type);
         intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 
+        // https://developer.android.com/guide/topics/large-screens/multi-window-support#launch_adjacent
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+        boolean adjacent = prefs.getBoolean("adjacent", false);
+        if (adjacent &&
+                context instanceof ActivityView &&
+                !((ActivityView) context).isSplit())
+            intent.addFlags(Intent.FLAG_ACTIVITY_LAUNCH_ADJACENT | Intent.FLAG_ACTIVITY_NEW_TASK);
+
         if (!TextUtils.isEmpty(name))
             intent.putExtra(Intent.EXTRA_TITLE, Helper.sanitizeFilename(name));
         Log.i("Intent=" + intent + " type=" + type);
@@ -1119,6 +1127,13 @@ public class Helper {
         if (task)
             view.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 
+        // https://developer.android.com/guide/topics/large-screens/multi-window-support#launch_adjacent
+        boolean adjacent = prefs.getBoolean("adjacent", false);
+        if (adjacent &&
+                context instanceof ActivityView &&
+                !((ActivityView) context).isSplit())
+            view.addFlags(Intent.FLAG_ACTIVITY_LAUNCH_ADJACENT | Intent.FLAG_ACTIVITY_NEW_TASK);
+
         if ("chooser".equals(open_with_pkg) && !open_with_tabs) {
             try {
                 EntityLog.log(context, "Launching chooser uri=" + uri +
diff --git a/app/src/main/res/layout/fragment_options_misc.xml b/app/src/main/res/layout/fragment_options_misc.xml
index e8648da249..a7b0362aba 100644
--- a/app/src/main/res/layout/fragment_options_misc.xml
+++ b/app/src/main/res/layout/fragment_options_misc.xml
@@ -2380,6 +2380,18 @@
                     app:layout_constraintTop_toBottomOf="@id/swMdn"
                     app:switchPadding="12dp" />
 
+                <androidx.appcompat.widget.SwitchCompat
+                    android:id="@+id/swAdjacent"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="12dp"
+                    android:checked="true"
+                    android:text="@string/title_advanced_adjacent"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/swAppChooser"
+                    app:switchPadding="12dp" />
+
                 <androidx.appcompat.widget.SwitchCompat
                     android:id="@+id/swDeleteConfirmation"
                     android:layout_width="0dp"
@@ -2388,7 +2400,7 @@
                     android:text="@string/title_advanced_delete_confirmation"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@id/swAppChooser"
+                    app:layout_constraintTop_toBottomOf="@id/swAdjacent"
                     app:switchPadding="12dp" />
 
                 <TextView
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 3cb9c6bfbc..dcfdf0375c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -919,6 +919,7 @@
     <string name="title_advanced_thread_by_ref" translatable="false">Thread by common reference</string>
     <string name="title_advanced_mdn" translatable="false">Process MDNs</string>
     <string name="title_advanced_app_chooser" translatable="false">Use Android app chooser</string>
+    <string name="title_advanced_adjacent" translatable="false">Open side-by-side</string>
     <string name="title_advanced_delete_confirmation" translatable="false">Permanent deletion confirmation</string>
     <string name="title_advanced_deletion_confirmation_hint" translatable="false">If you turn this off, please do not complain if you accidentally delete messages irreversibly</string>
     <string name="title_advanced_dmarc_viewer" translatable="false">DMARC viewer</string>