Need to indicate which tab has focus inside the pali widget

[bksubhuti]

User has multi window open.
If he clicks on the pali screen, the tab does not reflect the focus window pane.
User wants tab to have an indicator that the focus window has changed.

Maybe need to wrap tab with notifier and send the notification when window gets focus?
Requested by ven maggavihari

[bksubhuti]

Perhaps a spacer to align with left side of the window is best..
Here, in this picture, both tabs are next to the commentary..
Adding space would resolve the confusion.
Need to test with tab reorder (drag drop)