We've posted extensively about our experiences of working with Microsoft on their Remote Desktop Beta for Mac and how this is improving with each release.
However, we've also made no secret of our displeasure that Citrix have been unable to release a version of Receiver for Mac that will work with, not only FileMaker v16, but any SDI based app, such as Word and Acrobat together. This was reported to Citrix back in July last year.
However, we may have found a workaround, albeit with very limited testing. Citrix have a Chrome app that doesn't appear to suffer from the window handling problem that the native Mac app does (currently 12.8.1).
We need to do a lot more testing, but the initial results were encouraging. If anyone else is having similar issues, I'd be interested to know if this link helps: