I'm using NoScript 2.4.8, on Firefox 14.0.1, on Linux Mint, and on a fresh installation of Joomla 2.5, when I click the 'Add Image' button on the TinyMCE toolbar on the backend, I get a notification that says:
Sorry, but we have noticed that your popup-blocker has disabled a window that provides application functionality. You will need to disable popup blocking on this site in order to fully utilize this tool.
Quite annoying, as nothing is to be found on Google on this matter, and I have already Allowed (whitelisted) the website in NoScript. I had to manually enable and disable various add-ons before I found out that it was NoScript that was responsible for this.
Looking at the NoScript Options, I didn't notice any relevant option that could be responsible, so I post it here as a possible issue... I'll try to post this to Joomla and TinyMCE forums as well.