Probably related to this issue:
For More Information see: Shortcut for Layout disappear
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
I did not see this specific issue in the Forums or Issues sections, hence I made a new item. It's good to know that it might be related to another missing shortcut issue, and that someone might be working on it.
Frustrating to learn that the way "known" issues are actually tracked are as a separate, huge, Known Bugs List, which is itself a Single Issue Thread, started in 2010. I would have guessed that Known Bugs would be a top-level item? Maybe good for inside developers - not so good for FM customers trying to search for, then add an item. I'll not be wasting time among "Forums", "Issues" and "Known Bugs" databases again.
While you're free to "not be wasting time" with the Known Bugs list, you should understand that it was created and is maintained by PhilModJunk. He is not an employee of FileMaker and does this in his own time on a strictly voluntary basis.
And the database that is free to download from my drop box is much easier to search when the need to research a bug arises. Generally, one need only search the database, then check the most recent page of one of the two KBL threads for recent additions not yet added to the database to see what issues have been previously reported.