For Eee users,
when problems with screen sizes of dialogs in GRAMPS, the best is if you could take a screenshot and open a bug request on the bug tracker attaching the screenshot (picture with digital camara is also ok).
As Laura mentioned, a work-around in linux is:
1/ Press ALT while on the window, then move the window with the mouse.
2/ Right click in the task bar (KDE) and select move, then move the mouse to move the window
3/ Press ALT+F4 to close or if there is a cancel button also ALT+C to cancel (english version). Press ALT+O to access the ok button.