Quote: "Only if you use 3D objects."
Um... Did you even bother reading my post before you posted that...
The resolution of the GDK app and the resolution of the screen, and the client size of the GDK window are all completely separate things.
Both 2d and 3d objects are in GDK coordinates, and so changing the size of the window will scale them both, but it will also scale the results returned from dbMouseX()/dbMouseY() to counter for this change.
Changing the resolution of the window will affect everything, but DBPro will automatically adjust the 3d viewport, and so you won't notice a change for 3d things.
Changing the resolution of the screen will scale EVERYTHING, including windows coordinates, and so has no effect on the application (except if it is maximised, it will change the client size of the window).
If GDK is in fullscreen exclusive mode, then the resolution of the screen and the GDK resolution are forced to be the same.