Difficult to resize main window on Gnome3

On Gnome3 (not sure about other window managers), the area around the window borders and corners where the mouse allows resizing are incredibly narrow and make resizing very challenging. Diagonal resize is especially tricky and requires essentially single pixel accuracy with mouse to be able to get the diagonal resize cursor to become active.

Ref: Relates to issue identified using nedit-ng

https://github.com/eteran/nedit-ng/issues/291