Reaper Pan Bug:
Under option > Preferences > Appearance > Track Control Panels I have the Volume/pan > Pan fader unit display set for decibels (-90dB..+90dB)
To reproduce:
1. Open Reaper.
2. Set preferences as described above
3. Insert a track
4. Right click on the volume knob or fader to bring up the routing for track 1
5. In the pan where it reads “center” type in -10 or some number, and hit enter on the keyboard.
6. The results: The pan fader moves to the right +10. That’s backwards. It should move to the left -10, right?
Here’s a gif of what happens.