Windows 7 / 64 bit: Folder stays write protected after change

I really dont understand that: I have a folder, on which I want to REMOVE write protection, so that every application can write inside that folder. When I click on properties I can uncheck the checkbox "write-protected". When I click on "apply" there is a lot of processing done, because all child-folders will also be changed.

The wiered thing is, that when I click on properties again, the checkbox "write-protected" is again checked! What am I missing??