Hi Nader,
If this is only happening to one drawing then it is possible that it could be having issues. I would suggest to copy/paste your drawing in a new floor plan and test there to see if you are encountering the same issue. You could also contact our support department and have one of the agents take a closer look at the file to determine the issue. You can reach us at 1.866.697.2020
Regards,
Kris