(In reply to Nico Grunbaum [:ng, @chew:mozilla.org] from comment #3)
This may be hard to pull off and retain the history ordering information over the local and remote side. As it stands today (one column) you get a total ordering of the SDP history, so one can easily trace the flow, at the cost of making textual comparisons harder. The proposal would make comparisons easier, at the expense of ordering. Perhaps we could add a table above with the ordering, with links that would scroll the two columns to the selected SDPs?
I did include the relative timestamps so that you don't lose the ordering completely, but I agree that it does make it more difficult to trace the history. I'll have a look and see if I can get the ordering information and links working like you suggest. I had thought about that initially a bit and wasn't sure it was worth the extra effort because my primary use case is comparing SDPs, but if it is important to you, I'm sure it will be important to others as well.