Deletable folders

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

@@ -623,9 +623,8 @@ public class AdapterFolder extends RecyclerView.Adapter<AdapterFolder.ViewHolder
             if (Shortcuts.can(context))
                 popupMenu.getMenu().add(Menu.NONE, R.string.title_pin, order++, R.string.title_pin);
 
-            if (!folder.selectable && debug)
-                popupMenu.getMenu().add(Menu.NONE, R.string.title_delete, order++, R.string.title_delete)
-                        .setEnabled(folder.inferiors);
+            if (!folder.read_only && EntityFolder.USER.equals(folder.type))
+                popupMenu.getMenu().add(Menu.NONE, R.string.title_delete, order++, R.string.title_delete);
 
             popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                 @Override

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

@@ -353,7 +353,9 @@ public class FragmentFolder extends FragmentBase {
                 btnSave.setEnabled(true);
                 tvInboxRootHint.setVisibility(folder == null && parent == null ? View.VISIBLE : View.GONE);
 
-                deletable = (folder != null && EntityFolder.USER.equals(folder.type));
+                deletable = (folder != null &&
+                        !folder.read_only &&
+                        EntityFolder.USER.equals(folder.type));
                 invalidateOptionsMenu();
             }