events won't fire first time

[ton]

Hi,

I've developed a asp.net website in vs2008 in VB.

I use webserver controls in which I add standerd server controls inclusive
events on there behaviour.

When starting the site I show a page with a treeview in it and the first
node is in details shown on the right side of the screen
When clicking on a dropdownbox the normal behaviour would me a server site
code.

The problem is:
the first time the user got the website these events wont be executed

when he just clicks on the same node, the page is built up again
when he then change a value of a dropdownbox the event is fired and executed

It happens all the time. The initial page look the same but the
corresponding events won't fire correct.

Anyone got an idea?

Thanks

Ton