I'm unable to replicate the problem. Here is a simple example of many things I tried:
1. I created a Custom Menu set that removed Sort and Unsort from the Records menu.
2. I created a script that checks for a certain accont name, and if true, use the custom menu 1 set.
3. On a few layouts, for the script trigger, I used OnLayoutEnter to call that script.
4. I turn on file sharing.
5. On my iPad, I launch FileMaker Go, access the hosted file using the "test" user account.
6. The Layouts I access, I place my cursor in a field to edit, and Sort records is grayed out.
Perhaps you can let me know the exact functions that are not grayed out. Let me know what steps you took so I can try to replicate the issue.
I also have a dialogue to show the menu is installed correctly. I am attaching a couple of screen grabs.
I have the menu set installing as part of a startup script. Do you think that might be the problem?
Without seeing the script and the script triggers, it is difficult to determine why it isn't working the way you expected. If you want, send in a clone of your file and I'll take a look. Check your Inbox at the top of this page for instructions where to send the file.