This did not happen in Snow Leopard, but now on Mountain Lion (brand new computer) and fresh install of Firefox, I noticed the Download icon on the toolbar isnt displaying the progress bar when downloading. This happens when I set browser.download.useToolkitUI to true in about:config More details, I use tabs on bottom and I keep the download icon in the same toolbar as the tabs, right below the search box and above the scroll bar. In Firefox in its default settings, whenever downloading, the download icon would change to a small blue progress bar and a estimated of completion time. However, I changed the UItoolkit in about:config in order to display a small window when clicking the download icon, just like it used to be in older versions of Firefox. After this small change, the download icon stoped showing the progress bar when downloading. Is there something I can do to have the progress bar back, without changing the browser.download.useToolkitUI? Like I said, it used to work in Snow Leopard, this only happened in Moutain Lion.