I having a display problem with a flat style ComboBox contained in a Panel. The ComboBox displays incorrectly with a 3D border and is missing the dropdown arrow when I run my application under Windows XP. The ComboBox will temporarily repaint correctly if I move the form using the mouse off the edge of the screen then bring it back. Once I click where the dropdown arrow should be, the ComboBox reverts to the 3D effect. Can anyone advise me how to correct this? None of these behaviors occur when I run the application under Vista. The ComboBox is a standard .NET ComboBox with no property changes other than the FlatStyle property being set to âFlatâ. The control is not subclassed and has no custom event handlers. Both the Panel and the Form the Panel rests on have custom backgrounds. The application is set to use double buffering. Thanks for any help you can provide. Regards, Keith
Hi Keith, I'm not exactly sure what is happening, but I believe your problem is caused by the custom background. The documentation for FlatStyle even gives a warning for using FlatStyle.System, although there may be issues for FlatStyle.Flat as well. It may well be that the Flat style is just paint ontop of the 3D control which isn't triggered when it should. Try tweaking the background rendering, and perhaps call Invalidate on the ComboBox whenever the background is repainted. -- Happy Coding! Morten Wennevik [C# MVP] "Keith Furino" wrote: > I having a display problem with a flat style ComboBox contained in a Panel. > The ComboBox displays incorrectly with a 3D border and is missing the > dropdown arrow when I run my application under Windows XP. The ComboBox will > temporarily repaint correctly if I move the form using the mouse off the edge > of the screen then bring it back. Once I click where the dropdown arrow > should be, the ComboBox reverts to the 3D effect. Can anyone advise me how to > correct this? None of these behaviors occur when I run the application under > Vista. > > The ComboBox is a standard .NET ComboBox with no property changes other than > the FlatStyle property being set to âFlatâ. The control is not subclassed and > has no custom event handlers. Both the Panel and the Form the Panel rests on > have custom backgrounds. The application is set to use double buffering. > > Thanks for any help you can provide. > > Regards, > Keith > >
