After updating from Studio One 4.1.4 to 4.5, the UNO VST editor has trouble connecting to the synth.
If I create a new Song, and insert the VST Editor, it just says "Waiting for UNO", even when the MIDI settings are correct.
If I:
1. Create a new Song and insert the VST Editor
2. Save the Song and exit Studio One completely
3. Open Studio One and immediately load the Song
Then the VST editor is able to connect to the UNO. However, If I then close the song and re-open it (without exiting Studio One), it's no longer able to connect to the UNO. Same if I create a new song again and insert the VST.
So the only way to get the editor to talk to the UNO synth is by opening an existing song that already contains the VST.
I've double-checked all my MIDI settings, and I've also checked that this doesn't happen in Reaper or FL Studio, only in Studio One 4.5. The standalone editor also works fine every time. So this bug seems to be specific to Studio One 4.5.