Problem when Triggers are used in nested UpdatePanels - The content inside UpdatePanel is

Two things that stand out:

First, it should just be <ContentTemplate>, not <asp:ContentTemplate>.

Second, you have the "Go" button set as a PostBackTrigger (rather than an AsyncPostBackTrigger), so I would think that clicking on the Go button is refreshing the entire page (not using the UpdatePanel functionality).

Try fixing those two things and see if that gets you further. If not, try simplifying a bit... what if you just have a single UpdatePanel with a single button inside of it. Then try adding the nested panel. Then try adding the table. Piece by piece so you can see when it stops breaking. Good luck!

Oops, I meant "stops working," not "stops breaking." :-)