No freezing here on a windows 7 system with FileMaker 13.05 advanced install. Maximum zoom is 400%.
Maybe because I have quite a lot of graphic, layout objects on the layout?
Don't know. I will observe that at this point, you have not identified the OS your are using nor your version of FIleMaker.
I would also test this on different layouts and a brand new simple test file to see if this only happens on the one layout, all layouts in the same file or all layouts of all files.