Regarding the blank customize toolbar window, you may have a problem with an extension or theme. Try running Firefox in safe mode, this will help determine if there is a problem with a theme or extension. To do this, in the Help sub-menu click on "Restart with Add-ons Disabled", you will get a dialog box giving various options, just click on the "Continue in Safe Mode" button. Now see if the customize toolbar windows contains icons. If it does, to find out which add-on is causing that problem see https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes As for the other question, in Firefox 4 the refresh icon has been combined with the go and stop icons, and is attached to the right hand edge of he location bar. When you type in the location bar it shows the Go button, when a page is loading it shows the Stop button, at other time it shows the Refresh button. You can get separate buttons by opening the customize toolbar window and either dragging the refresh or stop button to a different location, or changing the order of the buttons from reload-stop to stop-reload.