I have a template that allows the client to add images to a template on their site. Since I've upgraded to 2.0 just one of the templates does nothing when you click on the Browse Server button in the dashboard. I have cleared my cache, cookies and ran sitescan.php to change all permissions without any luck. Any idea what could be causing the button to not load the image uploader lightbox?
Since, as you mentioned, only one template exhibits this problem, the reason should be confined to this very template.
Please see the dev console of Chrome on the problem page to find if any JS error is being thrown.
Also, using the same Chrome dev tools, try highlighting the HTML elements around the unresponsive button - possible there is some bigger transparent element overlaying the button thus causing it to be unresponsive.
Have you injected some custom code/HTML/JS in the template using the new admin tags of v2.0? If so, they also need to be scrutinized.
If nothing works, try making an exact copy of the template (with a new name). Remove all editable elements in it except the problem editable region. Register the test template. The browse button should be fine. Now try adding back the removed regions one-by-one. At one point, you should hit the problem and that would give you a clue.
Hope it helps.