New Post: How Does the Form Builder Go Full Width/Height?

There's a call to FunctionCallEditorManager.RegisterCustomCallEditor, there you pass a width and height parameters, if I remember correctly - null values either full screen, or auto adjusting the size.

namespace Composite.AspNet
{

[ApplicationStartup]
public class LoadUserControlStartupHandler
{
    public static void OnBeforeInitialize()
    {

    }

    public static void OnInitialized()
    {
        FunctionCallEditorManager.RegisterCustomCallEditor("Composite.AspNet.LoadUserControl",

"~/Composite/MyWebForms/Composite.AspNet.LoadUserControl/CallEditor.aspx",
null, 200);

    }
}