OK, I have been struggling with the KDE bug tracker thing looking for a report of a similar issue. I am not sure of where or how to report this issue using the KDE bug tracker?
Frequently, but not regularly, menus or dialogs display transparently. Meaning you can see an outline but nothing of the content. With menus this is most often not all of the menus of the application. When it happens to dialogs it is only rarely the whole dialog, most often with a dialog the window frame and background color will be there..
Sometimes a dialog will be visible, but when you attempt to select and modify some text on the form you get no visible feedback. But if you submit the form you will find that your update did happen. In this case I can work around the issue by resizing the form, then my selection and typing are echoed to the screen.
This issue does not happen all the time, or regularly. It comes and gos for hours at a time. I can suppress the issue by turning off the KDE desktop effects.
This is a Debian installation of KDE 4 that is I use every day.
- Allen