When I paste some text copied from a Gmail message into a new one, there's a thin grey frame around it.

http://i.imgur.com/velBw.png

I get this only in Chrome Dev and Canary (not in Chrome beta or Fx 4).

What is this 'feature'? Is it from Chrome or from Gmail?

Happened to me as well (I automatically pasted it into the url bar and copied it from there (without thinking, as I need to do that constantly when working in google docs (and yeah there is probably a paste plain text option available as well, but I have gotten used to this :D))). Either way, for non-power users it's quite a nice feature, although for users who want to re-use stuff it's kinda frustrating.

I think pasting the same copied text in Docs will also add a frame (a much uglier one).

David, you can past any text without its formatting by pressing Ctrl/Cmd+Shift+v. It's much easier than going through the omnibar IMO.

Ah, so that was the shortcut :P, I remember finding it once, but forgot about it and got used to cmd+(l->v->a->c) which is surprisingly fast actually (still slow in comparison to the proper shortcut though :D). Thanks :P!