Resolves a bug that was introduced with [1], furthermore and in
specific relation to the intent of said commit, this brings the
version selection combo box inline with other mod platforms.
[1] f7c144c393
Fixes GH-3118
Fixes GH-3720
Fixes GH-3731
Icons and Ok button state will now switch consistently when moving
between tabs. ATLaunchers packlist is now no longer redownloaded
each time you open its Tab. All lists are striped now. And all
search and filter fields now have a placeholder text.
