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.