Hello Daniel,
To create a special type of Panel control that will be semi transparent, you would need to create a VWG CustomControl that would inherit from the Gizmox.WebGUI.Forms.Panel and have a sligntly modified XSLT and CSS that would cause this new bahavior.
More specifically you would copy the current XSLT of the Panel control to your new CustomPanel control and change it slightly to use a CSS class that you will add in the CSS file of your new control.
This CSS class will cause the new Panel to be rendered with semi transparency.
To learn how to create such CustomControls, please view this article here.
Regards,
Ori Cohen
Support Manager, the Visual WebGui team