diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index da635218ab..c338c2383d 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -973,10 +973,10 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                     ibFlagged.setImageTintList(ColorStateList.valueOf(message.color));
             }
 
-            ibFlagged.setEnabled(message.uid != null);
+            ibFlagged.setEnabled(message.uid != null || message.accountPop);
 
             if (flags)
-                ibFlagged.setVisibility(message.folderReadOnly || message.accountPop ? View.INVISIBLE : View.VISIBLE);
+                ibFlagged.setVisibility(message.folderReadOnly ? View.INVISIBLE : View.VISIBLE);
             else
                 ibFlagged.setVisibility(View.GONE);
         }
@@ -1798,10 +1798,18 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                         if (message == null)
                             return null;
 
-                        List<EntityMessage> messages = db.message().getMessagesByThread(
-                                message.account, message.thread, threading && thread ? null : id, null);
-                        for (EntityMessage threaded : messages)
-                            EntityOperation.queue(context, threaded, EntityOperation.FLAG, flagged);
+                        EntityAccount account = db.account().getAccount(message.account);
+                        if (account == null)
+                            return null;
+
+                        if (account.pop)
+                            EntityOperation.queue(context, message, EntityOperation.FLAG, flagged);
+                        else {
+                            List<EntityMessage> messages = db.message().getMessagesByThread(
+                                    message.account, message.thread, threading && thread ? null : id, null);
+                            for (EntityMessage threaded : messages)
+                                EntityOperation.queue(context, threaded, EntityOperation.FLAG, flagged);
+                        }
 
                         db.setTransactionSuccessful();
                     } finally {
@@ -2443,8 +2451,8 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
             popupMenu.getMenu().findItem(R.id.menu_unseen).setEnabled(message.uid != null && !message.folderReadOnly);
             popupMenu.getMenu().findItem(R.id.menu_unseen).setVisible(!message.accountPop);
 
-            popupMenu.getMenu().findItem(R.id.menu_flag_color).setEnabled(message.uid != null && !message.folderReadOnly);
-            popupMenu.getMenu().findItem(R.id.menu_flag_color).setVisible(!message.accountPop);
+            popupMenu.getMenu().findItem(R.id.menu_flag_color).setEnabled(
+                    (message.uid != null && !message.folderReadOnly) || message.accountPop);
 
             popupMenu.getMenu().findItem(R.id.menu_copy).setEnabled(message.uid != null && !message.folderReadOnly);
             popupMenu.getMenu().findItem(R.id.menu_copy).setVisible(!message.accountPop);
diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index d9726530b9..9ac9f05c5f 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -212,17 +212,25 @@ class Core {
                                 case EntityOperation.SEEN:
                                     onSeen(context, jargs, folder, message, (POP3Folder) ifolder);
                                     break;
+
+                                case EntityOperation.FLAG:
+                                    onFlag(context, jargs, folder, message, (POP3Folder) ifolder);
+                                    break;
+
                                 case EntityOperation.ANSWERED:
                                 case EntityOperation.ADD:
                                 case EntityOperation.EXISTS:
                                     // Do nothing
                                     break;
+
                                 case EntityOperation.DELETE:
                                     onDelete(context, jargs, account, folder, message, (POP3Folder) ifolder, state);
                                     break;
+
                                 case EntityOperation.SYNC:
                                     onSynchronizeMessages(context, jargs, account, folder, (POP3Folder) ifolder, (POP3Store) istore, state);
                                     break;
+
                                 default:
                                     Log.w(folder.name + " ignored=" + op.name);
                             }
@@ -485,6 +493,14 @@ class Core {
         db.message().setMessageFlagged(message.id, flagged);
     }
 
+    private static void onFlag(Context context, JSONArray jargs, EntityFolder folder, EntityMessage message, POP3Folder ifolder) throws MessagingException, JSONException {
+        // Star/unstar message
+        DB db = DB.getInstance(context);
+
+        boolean flagged = jargs.getBoolean(0);
+        db.message().setMessageFlagged(message.id, flagged);
+    }
+
     private static void onAnswered(Context context, JSONArray jargs, EntityFolder folder, EntityMessage message, IMAPFolder ifolder) throws MessagingException, JSONException {
         // Mark message (un)answered
         DB db = DB.getInstance(context);