I have the same problem with master and Qt 4.7. Clicking the windeco icon on a window which is on either screen results in the menu displaying as far left on the left screen, and the top of the screen + (heightOfTitlebar) it seems. Simply right-clicking the titlebar itself results in an incorrect offset (resulting in it being on the left-most screen at the top. The difference is that the first one is statically always at left-top. The second case (sort of) follows the x axis of the titlebar, but at the top.
Anyways, ran it through gdb just for curiousity's sake and yeah mapToGlobal isn't giving what one might expect. Does the widget need a parent or something? Because other uses of it seem pretty similar to this one, yet they work fine. or is this some qt/x bug? -- Shaun Reich, KDE Software Developer (kde.org)