Hi Agnes,
I have reviewed your file, and was unable to reproduce the problem. It does not appear to be a problem with your model, but likely related to your LEAP installation. Prior doing a full reinstallation, I suggest to delete the area from your computer and then reinstall the area from the .LEAP file you sent us. To delete an area, go to Area -> Manage Areas, then find the file you are working on and delete it.
If you continue to have problems, please let us know.
Thanks,
Emily