Parent window goes null on Clicking TreeView child to Popup a window [ASP.NET]

Question

In my webpage I have a treeview with some items. When I clicking on a node I needs to open a Popup window and it is working fine. But the Parent window that contains the treeview goes to null. Why this happen so?

Answer 1

I think if you set this, your problem will be resolved

NavigateUrl="javascript://"

otherwise you need to post the code.