16028 settings and more context menu not accessible in ie10

[``* `#16028`Context menus in IE10 not accessible``](https://www.openproject.org/work_packages/16028)

This is a follow up branch of #2001 and fixes the tabbing for the settings and more menu (see [comment in the related ticket](https://community.openproject.org/work_packages/16028#note-16)).