Change stereo panning over time?

How do I change the stereo panning over time? Ideally I was hoping there would be a tool like the envelope tool where you could draw a line to determine where the stereo positioning is at any point on the waveform?

You can actually split the stereo track and use the envelope tool on the individual channels.
It is of course not equally convenient as a single control. Also, I don’t know if the two envelopes are preserved after recombining, if they are destructively rendered down or whatever.

I’m working with multiple mono tracks. I just want to be able to change their stereo position over time (rather than a master control). I suppose I could duplicate each track and use the envelope tool to set the volume of left and right, but that seems a very clumsy way of doing it.

I’m surprised there isn’t a standard feature for doing this. I’d have thought all musicians would want to be able to stereo-position each instrument in their recording?

There are plugins which pan … http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Amplify.2C_Mix_and_[b]Pan_Effects[/b]
pan LF0 2a GUI.png

Thank you.