disable useTargetedProductPolicyIfSeveralChildren

If Ruby general settings will be without titled border in RubyMine, user could think that all other debugger categories also about Ruby.
fix tests
restore open api + more consistency in naming
[git] cleanup: remove trivial javadocs
EA-57757 - assert: IconLoader.getIcon
We should not set CANCEL if popup can't be closed. Let's cancel it later.

The issue can be reproduced with the following steps:
1. Double-Shift
2. Type GUI
3: Select GUI Designer in Preferences
and popup stays opened...