Frameless not working when using QOpenGLWidget

We have a main window which subclasses Qtitan::RibbonMainWindow and we’ve tried every combination of ribbonBar()->setFrameThemeEnabled and ribbonBar()->setTitleBarVisible to get our application look like Office (context headers and quick access bar in the title bar). The default behaviour (that is, when the aforementioned methods aren’t called) is two titlebars on the top:
- The first titlebar is white and empty
- The second titlebar has everything (window handling icons, context headers, quick access bar, the title)
With the appearance of two titlebars, the status bar at the bottom is gone. The cursor seems to be one titlebar higher than it should be (example: you want to close the application and the close icon is in the second titlebar, you must move the cursor above it in the first titlebar).

The issue is caused by QOpenGLWidget; when it's closed, the window is drawn properly. Could you please have a look into this and fix it?

We use Qt 5.6.0, Qtitan 4.4.0, Visual Studio 2015 and Windows 10.

Could you please do the following for your application?

QApplication app( argc, argv );
app.setAttribute( Qt::AA_NativeWindows );

The bug still exists?

Thank you, the bug disappeared.