In the current implementation if you rename your file your discussions will become disconnected from the file. The discussions will not be lost but they will not be available through the file anymore. This is a limitation that we will address in future releases. This is a use case we would like feedback on as well as there are cases where you would want to keep the discussions related to the new file and cases where you would not.

Yes this is correct. Currently we rely on the file name no changing. This is something we are speaking with people about how this should work.

Yes when you save a file from a discussion if you want the discussions to show in the downloaded file you must remove the number from the file.

Currently there is no method to delete these relationships. This is someting we are working on. If you really want to delete the relationship between discussions and parts then you can delete the part and all it's reltionships will be gone.

This is something we are working on improving. Currently the only way to know what what Parts a Discussion is already related to is to open the "Relate to Part" dialog box and look to see what is already selected.

There is a work around which is to refresh the window. Once you refresh the browser you should be able to activate/type. We are working on a fix.