this always worked until this morning. When I'm running gmail in firefox, now when I compose an email and click on the attach file button, nothing happens--no window pops up for me to select a file. I've tried uninstalling and installing the latest version of firefox, and it hasn't helped. this works fine in IE. When I click on other buttons in the compose message screen, like to insert a photo, the window pops up fine. It's only the attach file that no longer works. I've tried looking behind all open windows to make sure attach file window isn't hiding.