I have a menu that I have setup to enable dragging of elements. It all works fine until I open my menu. If I open the menu, which is setup as click to open and then try to drag a node in my treeview I get the following error.
Sys.WebForms.PageRequestManagerServerErrorException: Conversion from string "null" to type 'Integer' is not valid.
Sys.WebForms.PageRequestManagerServerErrorException: Conversion from string "null" to type 'Integer' is not valid.