[72deluxe]

Thunderbird does support this. You're using the "Search" box in the UI - use ctrl-shift-F to search in Mail and choose "match any of the following" in the UI and specify 2 rules - one for to, one for from. The Search from the main window's search box isn't that useful - the "find in mail" is much better.

[MayeulC]

Wow, this looks so much better, thank you. The search box isn't very usable, yet that's the only thing I discovered until now.

It doesn't help that, at least the French version, the menu entry for that function is cut (and looks like "search in m..."). "Advanced search" (the window title) sounds like a more descriptive and better title.

[72deluxe]

Yes the main search on the main window is rather useless by comparison. It provides far too much noise.