I am trying to use the UVI Workstation with Renoise. Whenever I try to drag and drop midi data from a slice sample though, Renoise insists on closing the current file and opening a new one, which is not at all what I want. Is there any way to override this behavior?
Afaik: for now there is no way to override this. This has come up with other software too, that deal with drag&dropping midi. The suggested workaround being a copy paste from the new project into the destination project.
This is quite a big issue, and a serious showstopper for me. I also see that several people have complained about this already, so what are the chances of this being fixed anytime soon?
Probably very hard, because Renoise is just one frame in the lower graphical control area (Like DirectX) so it doesn’t get a signal from the OS “where” a midi file got dropped, just that a midi file has been “dropped” on the Renoise window.
Most other software simply use the platform its common dialog API for their visualisation and with those dialogs, the OS supplies you with much more information including mousecoordinates.
It would indeed be nice if Renoise would at least ask you what to do with the file, but i suspect a lot of people will find that annoying as well (that it can’t detect that you dropped the file onto a certain area) but i doubt it can get any better than that.
Can’t the midi be inserted at the cursor? Like what happens with samples being droped in renoise (in the instrument window).
Also, would it be possible the other way around, like export one track of a pattern or song to exporer?
This would be great for storing good melodies that don’t get used in the current song 
No, because a midi file is a song file originally and a midi file can consist out of one track or more, but if a midi file contains only one track, that doesn’t automatically mean it is a track-snippet.