There are a couple of ways to get that feature.
In SKS6 you can add a titlebar button and set it's function to rollup. How you do this depends on if you are using UIS2 windowframes or Perpixel frames.
You can also set that function in Windowblinds. Just go to the 'settings' tab and at the bottom there are a couple dropdown lists. You can set the rollup function there. That way, all your windowblinds will have that feature.
