BUR #20037 has been approved by @nonamethanks.
rename shutter -> window_shutter
rename open_shutters -> open_window_shutter
The wikis says so, as well as the the usage respective tags. Requested the renaming in order to prevent other users from using it on random shutters like camera shutters, etc. I don't feel like renaming these tags into the plural form, even Wikipedia uses the singular form. There can be a case when a window uses a single shutter.
Updated