Workspace Widget does not work with Synfig Studio 1.4.0, Microsoft Surface, Windows 10

It works in Version 1.2.0, but not 1.2.2 or 1.4.0.
Apparently, the coordinates of the mouse pointer are calculated wrong.
The four rectangles do not become green when the mouse pointer is at them. It works to some degree in full-screen mode, on a single screen. In this case, it helps to move the pointer about 40 pixels below the rectangle, and it turns green then.
Additionally, the icon which moves with the mouse in 1.2.0 is stuck to the top left corner of the screen. Already in 1.2.0, it did not properly follow the mouse on the second screen, but the distance varied.

Ok, I have found out more. It works if the top left corner of the window contents is placed exactly at the top left corner of the screen. You are working with screen coordinates, where you should work with window content coordinates.