Update MathCATPreferences.py

Reinstate line deleted in error for continued keyboard event handling

Author: ways2read

NVDA-addon/addon/globalPlugins/MathCAT/MathCATPreferences.py

@@ -228,4 +228,6 @@ def MathCATPreferencesDialogOnCharHook(self,event):
             self.m_listBoxPreferencesTopic.SetFocus()
             #jump out so the tab key is not processed
             return
+        #continue handling keyboard event
+        event.Skip()