fix undo, allow main window focusable

ankiqt/ui/main.py

@@ -928,6 +928,7 @@ class AnkiQt(QMainWindow):
         self.currentCard = None
         self.deck.s.flush()
         self.lastCardBackup.toDB(self.deck.s)
+        self.deck.rebuildCounts()
         self.reset()
 
     # Other menu operations

designer/main.ui

@@ -144,7 +144,7 @@
           </size>
          </property>
          <property name="focusPolicy" >
-          <enum>Qt::ClickFocus</enum>
+          <enum>Qt::TabFocus</enum>
          </property>
          <property name="frameShape" >
           <enum>QFrame::NoFrame</enum>