User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:188.8.131.52) Gecko/20100315 Firefox/3.5.9 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:184.108.40.206) Gecko/20100611 Firefox/3.6.4 (.NET CLR 3.5.30729) A menupopup element built from a RDF template will distort its ancestor menupopup elements when displayed in Firefox 3.6. Reproducible: Always Steps to Reproduce: 1. Create an example XUL file which builds a menu with a submenu from a RDF template. 2. Open the menu then expand the submenu. 3. Compare the outcome between Firefox 3.5 and 3.6 Actual Results: When the menupopup element for the submenu is displayed, it's contents are also added horizontally to the original menupopup. Expected Results: The menu should look the same as it does in Firefox 3.5 The submenu should not alter the parent menu when displayed.