in QT_version < 5 the "setUnifiedTitleAndToolBarOnMac" was set

If set to true, then the top toolbar area is replaced with a Carbon HIToolbar or a Cocoa NSToolbar (depending on whether Qt was built with Carbon or Cocoa). All toolbars in the top toolbar area and any toolbars added afterwards are moved to that. This means a couple of things.

QToolBars in this toolbar area are not movable and you cannot drag other toolbars to it
Toolbar breaks are not respected or preserved
Any custom widgets in the toolbar will not be shown if the toolbar becomes too small (only actions will be shown)
Before Qt 4.5, if you called showFullScreen() on the main window, the QToolbar would disappear since it is considered to be part of the title bar. Qt 4.5 and up will now work around this by pulling the toolbars out and back into the regular toolbar and vice versa when you swap out.

Setting this back to false will remove these restrictions.

[QMainWindow Class Reference] http://qt-project.org/doc/qt-5/qmainwindow.html

[d379f3]: Merge branch 'bug-18517-qt5ToolBarStyleAdaptions'

Merged commits:

2014-12-09 14:49:04 Jonas Cordes [7e932e]
set UnifiedTitleAndToolBarOnMac to default (false) if qt version > 5

User cordes has pushed new remote branch:

bug-18517-qt5ToolBarStyleAdaptions