diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index 1cbdc4c0b1..78ccbfe280 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -1216,8 +1216,9 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
             if ("expanded".equals(name)) {
                 // Collapse other messages
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
+                boolean expand_all = prefs.getBoolean("expand_all", false);
                 boolean expand_one = prefs.getBoolean("expand_one", true);
-                if (expand_one) {
+                if (!expand_all && expand_one) {
                     for (Long other : new ArrayList<>(values.get(name)))
                         if (!other.equals(id)) {
                             values.get(name).remove(other);
@@ -3162,6 +3163,12 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
 
                     iProperties.setValue("expanded", expand.id, true);
                 }
+
+                boolean expand_all = prefs.getBoolean("expand_all", false);
+                if (expand_all)
+                    for (TupleMessageEx message : messages)
+                        if (message != null && message.ui_seen)
+                            iProperties.setValue("expanded", message.id, true);
             }
         } else {
             if (autoCloseCount > 0 && (autoclose || onclose != null)) {
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsBehavior.java b/app/src/main/java/eu/faircode/email/FragmentOptionsBehavior.java
index d2fb9db814..b626ce02f4 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsBehavior.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsBehavior.java
@@ -46,6 +46,7 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
     private SwitchCompat swSwipeNav;
     private SwitchCompat swReversed;
     private SwitchCompat swAutoExpand;
+    private SwitchCompat swExpandAll;
     private SwitchCompat swExpandOne;
     private SwitchCompat swAutoClose;
     private Spinner spOnClose;
@@ -57,7 +58,7 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
     private SwitchCompat swDiscardDelete;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "pull", "autoscroll", "doubletap", "swipenav", "reversed", "autoexpand", "expand_one", "autoclose", "onclose",
+            "pull", "autoscroll", "doubletap", "swipenav", "reversed", "autoexpand", "expand_all", "expand_one", "autoclose", "onclose",
             "collapse_single", "collapse_multiple", "autoread", "autounflag", "automove", "discard_delete"
     };
 
@@ -77,6 +78,7 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
         swSwipeNav = view.findViewById(R.id.swSwipeNav);
         swReversed = view.findViewById(R.id.swReversed);
         swAutoExpand = view.findViewById(R.id.swAutoExpand);
+        swExpandAll = view.findViewById(R.id.swExpandAll);
         swExpandOne = view.findViewById(R.id.swExpandOne);
         swAutoClose = view.findViewById(R.id.swAutoClose);
         spOnClose = view.findViewById(R.id.spOnClose);
@@ -135,6 +137,14 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
             }
         });
 
+        swExpandAll.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("expand_all", checked).apply();
+                swExpandOne.setEnabled(!checked);
+            }
+        });
+
         swExpandOne.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -261,7 +271,9 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
         swSwipeNav.setChecked(prefs.getBoolean("swipenav", true));
         swReversed.setChecked(prefs.getBoolean("reversed", false));
         swAutoExpand.setChecked(prefs.getBoolean("autoexpand", true));
+        swExpandAll.setChecked(prefs.getBoolean("expand_all", false));
         swExpandOne.setChecked(prefs.getBoolean("expand_one", true));
+        swExpandOne.setEnabled(!swExpandAll.isChecked());
         swAutoClose.setChecked(prefs.getBoolean("autoclose", true));
 
         String onClose = prefs.getString("onclose", "");
diff --git a/app/src/main/res/layout/fragment_options_behavior.xml b/app/src/main/res/layout/fragment_options_behavior.xml
index 57c2fd770f..d6600059c1 100644
--- a/app/src/main/res/layout/fragment_options_behavior.xml
+++ b/app/src/main/res/layout/fragment_options_behavior.xml
@@ -93,6 +93,17 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/swAutoExpand" />
 
+        <androidx.appcompat.widget.SwitchCompat
+            android:id="@+id/swExpandAll"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_advanced_expand_all"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/tvAutoExpandHint"
+            app:switchPadding="12dp" />
+
         <androidx.appcompat.widget.SwitchCompat
             android:id="@+id/swExpandOne"
             android:layout_width="0dp"
@@ -101,7 +112,7 @@
             android:text="@string/title_advanced_expand_one"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/tvAutoExpandHint"
+            app:layout_constraintTop_toBottomOf="@id/swExpandAll"
             app:switchPadding="12dp" />
 
         <androidx.appcompat.widget.SwitchCompat
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 7eaa8fa68e..a19539c184 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -275,6 +275,7 @@
     <string name="title_advanced_swipenav">Swipe left/right to go to next/previous conversation</string>
     <string name="title_advanced_reversed">Reverse navigation direction</string>
     <string name="title_advanced_autoexpand">Automatically expand messages</string>
+    <string name="title_advanced_expand_all">Automatically expand all read messages</string>
     <string name="title_advanced_expand_one">Expand only one message at a time</string>
     <string name="title_advanced_collapse_single">Collapse single message in a conversation on \'back\'</string>
     <string name="title_advanced_collapse_multiple">Collapse multiple messages in a conversation on \'back\'</string>