NSTabView patch redux

[Adrian Robert]

Hi,

This is the second iteration of a small patch to NSTabView to bring 
behavior in line with OS X:

  - handle case with zero tabs or last tab removed: do not crash if 
start with no tabs, and display blank rectangle here or when last tab 
removed

  - call for redisplay on add/remove tab (even if selected tab does 
not change)

Note: as indicated in comments, this could be refined further to try 
determining the exact rectangles that need to be displayed in various 
cases.  I'm holding off on that for now.

If anyone wants to try it, I have a small test app for GS and OS X.

<nsTabView_display.patch>

nsTabView_display.patch
Description: Text Data