Weird object selection, bug or feature? (SVN build)

I just noticed something weird a week ago and its still there in 2.62.3 r45187.

If I press “a” to deselect all objects, then use “b” (or the lasso selection) to select an object other than the last selected and press “tab” to edit it, it will instead edit the last object which was selected by clicking on it.

The new object also has a white outline instead of orange, but I can move it, etc.

Is this how it is supposed to be, or did I stumble upon a bug?