Review z-index with dropdown menus

[nicolepaschen]

A few customer contacts have come thru where the dropdown menu was behind the page content on the screen.

[jamesros161]

We have made a lot of changes to the z-index and related issues with dropdown menus in the last few releases. I wasn't able to replicate this, so it may have already been resolved. Added this to the 'Needs Testing' just so we can double check it during the testing.