Prevent crash

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

@@ -1523,6 +1523,12 @@ public class FragmentMessages extends FragmentEx {
                     model.setMessages(messages);
                 }
 
+                if (selectionTracker != null) {
+                    PagedList<TupleMessageEx> current = adapter.getCurrentList();
+                    if (messages.size() != (current == null ? 0 : current.size()))
+                        selectionTracker.clearSelection();
+                }
+
                 Log.i(Helper.TAG, "Submit messages=" + messages.size());
                 adapter.submitList(messages);