Improvements to tab visibility calculation when switching tabs.
Improvements to tab visibility calculation when switching tabs.

skyglobal/web-toolkit,image-tester/web-toolkit,aldreth/web-toolkit,aldreth/web-toolkit,aldreth/web-toolkit,image-tester/web-toolkit,image-tester/web-toolkit,skyglobal/web-toolkit,skyglobal/web-toolkit