After some experimentation a while back, I returned to the subsites module this week (using the latest repository version) and was pleasantly surprised to find support for assigning ownership to asset folders to particular subsites.
However, the one place it doesn't seem to entirely be applied is when attaching images in the content editor (tinymce), with the attachment right pane pop-up window - specifically the drop-down folder selection and default folder. Now, selecting a folder the subsite has no access to does filter out entries (though uploading to such a folder appears to hang rather than yield an error), but I'd rather such folders were hidden in the first place, and that the default folder was one owned by the subsite (rather than the top level folder). In my setup, each subsite will have a single asset folder.
Can anyone provide a hint as to where I might start tweaking the code for this. I'm willing to make local modifications but am having a little trouble identifying just where I want to be working in the code.
Thanks for any pointers.