Small improvement

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -1160,7 +1160,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
                     if (!message.folderReadOnly) {
                         bnvActions.getMenu().findItem(R.id.action_delete).setVisible(
-                                (delete ? message.uid != null || message.msgid != null : message.uid != null));
+                                (delete ? message.uid != null || !TextUtils.isEmpty(message.msgid) : message.uid != null));
                         bnvActions.getMenu().findItem(R.id.action_delete).setTitle(
                                 delete ? R.string.title_delete : R.string.title_trash);
 

app/src/main/java/eu/faircode/email/FragmentFolders.java

@@ -25,6 +25,7 @@ import android.content.SharedPreferences;
 import android.graphics.Color;
 import android.graphics.Rect;
 import android.os.Bundle;
+import android.text.TextUtils;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -568,7 +569,7 @@ public class FragmentFolders extends FragmentBase {
                     List<Long> ids = db.message().getMessageByFolder(folder);
                     for (Long id : ids) {
                         EntityMessage message = db.message().getMessage(id);
-                        if (message.msgid != null || message.uid != null)
+                        if (message.uid != null || !TextUtils.isEmpty(message.msgid))
                             EntityOperation.queue(context, message, EntityOperation.DELETE);
                     }
 

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -3024,7 +3024,7 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
         // Mark duplicates
         Map<String, List<TupleMessageEx>> duplicates = new HashMap<>();
         for (TupleMessageEx message : messages)
-            if (message != null && message.msgid != null) {
+            if (message != null && !TextUtils.isEmpty(message.msgid)) {
                 if (!duplicates.containsKey(message.msgid))
                     duplicates.put(message.msgid, new ArrayList<TupleMessageEx>());
                 duplicates.get(message.msgid).add(message);
@@ -4455,7 +4455,7 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                     List<Long> ids = db.message().getMessageByFolder(folder);
                     for (Long id : ids) {
                         EntityMessage message = db.message().getMessage(id);
-                        if (message.msgid != null || message.uid != null)
+                        if (message.uid != null || !TextUtils.isEmpty(message.msgid))
                             EntityOperation.queue(context, message, EntityOperation.DELETE);
                     }