title: ExtJS 4 GroupingSummary How To Deactivate Expand on Summary Row Click
body: <p>I have an ExtJS 4 grid with GroupingSummary Feature. ExtJs Default is grid is expanded when user clicks on any cell in grouping row. I want to disable this feature, no expansion should take place except when user clicks on designated 'expand' icon. How do I accomplish this?
  There is the 'groupclick' event, is there a way to override its default behaviour and do nothing / remove it?
  Thanks in advance</p>