I've got an ajax manager and a single loading panel on the page. The manager ties a bunch of radgrids together. Problem I'm having is that I hide/show some of them based on the state...but the loadingpanel gifs always showup regardless of grid visiblity
Why don't you wrap these grids into a single Panel and ajaxify it instead of each grid separately?
if your grids are not so closely located on the page, then you could try wrapping each into always visible Panels and ajaxify the Panels. I have heard once that the controls added to the ajax settings is suggested to be always visible on the page.