GridBagLayout flickers when resizing

[Peter Moncure]

When resizing a group box which uses the GridBagLayout, if it contains a large number of controls, (greater than ~20 controls), the group box title and border flickers horribly. Drop-down list buttons also flicker. This happens when I hold the window frame and resize the window back and forth.

If run this on multiple machines in the office with identical results. My machine is an AMD 2400 with 1 Gig of memory, so I'm confident its not a speed problem.

Looking at the code it seems that only the Layout event is handled by GridBayLayout. Can I possibly cut down on the flicker by handling the paint event and use double-buffering? If so, why doesn't the GridBagLayout handle the Paint event?

TIA

[Ramesh Praveen]

Peter,

Could you attach the sample form where you see this flicker? We could then be sure that we are talking about the same thing. We will then see if anything can be improved in the layout logic or if double buffering will help.

Thanks
Praveen

[Peter Moncure]

Attached is a solution in which 2 Group Boxes display this flickering behavior.

Your help is greatly appreciated.

> Peter,
>
> Could you attach the sample form where you see this flicker? We could then be sure that we are talking about the same thing. We will then see if anything can be improved in the layout logic or if double buffering will help.
>
> Thanks
> Praveen

[Ramesh Praveen]

Peter,

This seems to happen when you set the FlatStyle to System for the GroupBox. Otherwise it doesn't flicker. I am note sure if setting the double-buffering style will help because the drawing is done natively by the OS (when System).

Regards,
Praveen

[Peter Moncure]

>
> This seems to happen when you set the FlatStyle to System for the GroupBox. Otherwise it doesn't flicker. I am note sure if setting the double-buffering style will help because the drawing is done natively by the OS (when System).

Great! That fixed the problem with the Group Boxes, (not sure that having the group boxes flat actually does anything anyway). But I still see the flicker in the buttons of the ComboBoxExt controls, no matter which border style I use. I do not see any flicker in the stardard Windows Form Combo boxes, just the Syncfusion ComboBoxExt.

I've tried setting the form's style to turn on double-buffering but that doesn't seem to help.

Thanks again for your assistance.

[Ramesh Praveen]

Peter,

I noticed that if the parent GroupBoxes have the FlatStyle set to Standard then the child comboboxexts don't flicker. Could you please double check?

Thanks
Praveen