Merge pull request #1418 from ZER0/toolbar-not-customizable/966727

fix Bug 966727 - Toolbar created by sdk/ui should not be customizable r=@gozala
Merge pull request #1398 from ZER0/anchored-panel/907450

fix Bug 907450 - Anchored Panels r=@gozala
Bug 963111 - Toolbar should be able to accept buttons as well, other than frames

- Added test case