In Forms Designer, using a custom control that inherits GLControl crashes visual studio

[resHQ]

encountered in visual studio 2019.

Forms designer actually calls the subscribed events when you do stuff like clicking, resizing the control that inherits/has a glcontrol.

To stop it from crashing:
make a private bool isInDesignMode = (LicenseManager.UsageMode == LicenseUsageMode.Designtime);

and then do a if(isInDesignMode) {return} check before any other logic, in the affected methods (examples are onResize, onPaint).