If someone is trying to use/install KDS v3.0 on the public beta (4) of OS X El Capitan (10.11), you'll probably have a problem at the workspace selection.
As i found no information about this on the Internet, but solved the problem, here is my solution.
To resolve this problem, I modified the file located here:
"/Applications/KDS_3.0.0.app/Contents/eclipse/kinetis-design-studio.ini" and removed the lines 7 and 8:
Kinetis Design Studio
With that modification, the splash screen is not display and you should be able to choose you workspace and use KDS.
Thank you so much for that comment.
Was sitting here with a "DeaD" KDS on El Capitan beta 8, which locked up after the splash screen had disappeared, did what you suggested and now works.