label is shown even under a panel or groupbox

Original Reporter info from Mantis: baldzhang @baldzhang

• Reporter name: bald zhang

Description:

recently upgrade my development environment to 2.0.x, when design some testing app, found this issue.

a label on form, under a panel or a groupbox, it SHOULD hidden but it shown, both design time and run time.
if put a memo, the label was covered.

1.8.4 win32: good
2.0.8 win32: has issue
2.0.8 gtk2-linux: good.
trunk qt5-linux: has issue

haven't check every components.

Steps to reproduce:

put a label on form
put a panel(or a groupbox), move the panel over the label, the label is still shown.

Mantis conversion info:

• Mantis ID: 37151
• Platform: Windows, Linux
• Version: 2.0.8