[Kst] [Bug 116847] Problem with X/Y Mouse Zoom mode

[Andrew Walker]

The problem is that the clipping wasn't being forgotten, but getting cached.
The menu has to overlap with a plot region, and when you select the
Y Mouse Zoom mode the cursor has to have a plot located within it.
When the menu is closed your mouse has to remain with the same plot.
Sometimes it has to be done twice, and you'll see the problem only the
second time.