Usercontrol hang when changing height of control

Hello,

I'm not sure if this thread right in the group, but I will try it.
I created with VB2008 and interoptusercontrols a Control that I use in VB6 in same forms.
In one of them are have two of this control. When I open this form the first time and change the
height of one of this control (on runtime), then my application hangs. I have to click on my app and a switch-to window
appears. With a click of this window the control will shown.

Is there any idear to solve this problem?
Best regards

Michael