General Discussion • Making a window's background transparent breaks -moz-window-dragging (Windows)

I'm looking into creating a UXP application with a custom window frame style, one that is not rectangular. I have chromemargins="0,0,0,0" on the window and -moz-window-dragging: drag; on a child element (which has a rounded border). This works until I set the background of the window to transparent. Once I do that, I can only move the window through Windows's system menu. The default resize corners break as well. Is there any way I can get a non-rectangular window frame without resorting to having my own moving/resizing code?

I have only tested this on Windows, not on any other platforms.