This one was just recently reported by others.
For More Information see: Field cut off in WebDirect
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Thank you for your post.
As PhilModJunk reported, this was recently reported (Thank you!).
I have also attached your post to the original report. When more information becomes available, I will let you know.
This pop-up menu issue with Web Direct has been fixed in FileMaker Server 14.0.1.