I'm having a similar problem.
I'm trying to set a transparent loading panel for a prometheus grid.
I've seen in this
example that if I want a loading panel I have to define the loading panel in a separate label, and I have to include the object I want loaded in a RadAjaxPanel.
In the provided example, the loading panel is applied on a calendar and on a GridView and I have no problems with them. My problem comes when I set a prometheus radGrid. At first the intellisense from visual studio marks the grid labels as error or unknown labels, and when I execute (with no compiling errors), the loading panel is completely solid.
Is there any way to make it work just as the old grid?