Product and version: Filemaker 18.104.22.168 64-bit
OS and version Windows 10 64-bit
1. Create Popover button in Layout A.
2. Insert a merge field as the label of the popover button
3. Give the popover button a coditional hiding clause in the inspector
4. Save the layout
5. Go back into layout mode, copy the button.
6. Navigate to a different layout.
7. Paste the button.
8. The popover button no longer has it's hiding clause, and Filemaker becomes unstable
9. You can cause filemaker to immediately crash at this point if you try and delete the button you just pasted.
10. After recovery, the button is still in the layout where you pasted it. If you try and delete it again, filemaker will once again crash.
How to replicate
I have created a sample file:
Use button bar popup instead.