• open SourceTree window maximized
• hover mouse over left or right border
• mouse cursor changes to resize cursor
• resize the window
• window is now in a strange state, restore icon is not changed to maximize icon
• only after vertically resizing the window, it can be maximized again

I have two monitors with different sizes. When the main window is resized as described above, a remainder of the window is painted on the other monitor, even after it is maximized again on the first monitor.

You can not drag the window to a second monitor when maximized by grabbing it at the title bar. Hot keys work though.

And last but most upsetting: The maximized SourceTree window prevents the Windows taskbar from appearing. (I have it set on auto-hide and at the bottom.)