macOS: Qt 3D Studio Look'n'Feel is Wrong

See the attached screenshot, the macOS look'n'feel differs from the intended (the one we have on Windows). Here are at least some observations:

• Dockable panel titlebar has light gray color making it impossible to read the text of the titlebar.
• Dockable panel titlebar icons look wrong.
• There is wasted space (looks like status bar area) at the bottom of the app window.