Hi Bonnie, I modified your if statement to what I think you meant ( does that make sense ? ) just so it would compile but I receive the same error as I did using my code which is "Unable to cast object of type TabPages.PJKTabPage to type TabPages.PJKTabPage", something I'm missing here ! thanks again

if (type.IsSubclassOf(type.GetInterface("PJKPlugins.ICMSTabPage")))