User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 Once you run a secondary Firefox instance while there is any dialogbox pretty much like a 'file upload' left in the previous Firefox window, newly opened window won't show bookmarks toolbar and adress bar will lost its function. Reproducible: Always Steps to Reproduce: 1. Run Firefox. 2. Open any common dialogbox (Open File, File Upload, Save As). 3. Window will be disabled not to allow you to open another window or tab in same instance, so run another firefox instance. Actual Results: - Bookmarks toolbar won't be loaded in new instance. - Adress bar will loose its function. Expected Results: It must work properly.