Bug 1225504 xenea theme, z-index prevents theme menu from working.
Remedy:
1. Set a z-index 211 at the #optionsmenu level and remove all subordinate z-index statements.  This resolves the bug.
2. Set a z-index 210 at the #topMenu level and remove all subordinate z-index statements.  This improves maintainability.
 #1198836 - Version numbers required for CSS files
Merge branch 'master' of https://github.com/fisharebest/webtrees