Hi,
That ‘gray box’ problem usually only occurs in hidden containers, like hidden tabs in a tab control. I haven’t seen that problem occur in the widget area before.
Do you have a URL so I can see the problem?
If the issue is a javascript control then the mapp0.resize() call goes in the javascript code for the control. But I can’t tell you where to put it because all controls are different. For tabs I do have a workaround in the plugin – it will respond to the tab show events if you use jQuery UI tabs or a plugin based on that library.