That just taught me a new trick. I have long wanted to be able to "tweak" table occurrence positions and your post provided just enough info for me to figure out that ctrl-arrow works to move them around in Windows Systems.
Fortunately for me, the issue report appears to be Mac only as I can use ctrl-arrow key combinations to move the occurrence boxes and the position changes are saved when I close and re-open the Manage | Database window.
Thank you for your post.
I can replicate this issue using FileMaker Pro 13.0v1 on Mac OS X 10.9.2 and Mac OS X 10.8.5. This issue does not occur under Windows 7.
Using FileMaker Pro 12, the key combination is different (control-option), and the issue does not occur.
I discovered that if after I move the table, if I let go of Command-Option keys and press any arrow key once, although nothing appears to happen, the table position is then saved.
I have forwarded your post along with my findings to our Development and Testing departments for review.
An entry in the Known Bugs List has been linked to this Issue Report. Any Comments/Questions/Suggested Corrections should be posted here or in a new thread. Please do not post such comments to the Known Bugs List thread.