We're using TinyMCE 4.3.2, but TinyMCE is up to version 4.6.7 as of the creation of this issue. Our version is almost two years old, so it's a good idea to upgrade to take advantage of bug fixes.
The version used in the merged pull request is 5.0.16.
Retroactive testing notes:
Check that TinyMCE does not switch to a more limited mobile version on mobile devices ().
Check that TinyMCE does not override the browser's context menu ().