Custom Screen Issue

I am having a unique custom screen issue. I have a custom screen that is built using .Net. This screen has a listbox on it. The idea behind this, is that when I fire off a Gridview row command, it takes the listbox.selectedindex and then does a bunch of stuff. All of the functionality works fine for me in debug and also works if I hit the page directly through IE9. It does not work in Tessitura.

 Here is the real kicker, It does work in Tessitura for my co-worker. We both have 64 bit machines and both use IE9 if that has anything to do with it. I have also tried the Tessitura Drop down fix where you modify the registry for “Feature_Use_WindowSelectedControl” but no change.

I ran a .Net trace on it when trying it from Tessitura and for the listbox under “Form Collection” the listbox comes up “undefined” where when I run the same trace from IE, the listbox displays the selected index.

This used to work for me in Tessitura but have since upgraded to IE9 so I am thinking that may be the issue but not sure if Tessitura uses the IE engine that is installed on my machine or something so I am a little lost.

Any ideas?

Thanks!