thanks for your help in advance.
the groupbox is bigger and bigger when i set autosize =true.
1. drag a radgroupbox into form
2. drag 3 radpanels into radgroupbox
3. set the 3 radpanels' dock = dockstyle.top
4. set radgroupbox. autosize = true
5. drag a radbutton into form and out of radgroupbox
6. add click eventhandler to radbotton with below code
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
RadPanel2.Visible = Not RadPanel2.Visible
7. run app, click the button continuously, you can find the width of groupbox is bigger and bigger.
what is wrong and how to avoid ?