Border Select keyframes in Action Editor I am having trouble selecting multiple keyframes in the action editor spread over multiple channels. I have tried with all channels selected/deselected but with no luck. Is there a trick in order to get border select working across multiple channels.

Here is my attempt to border select, after which I individually select keyframes.
You need to unpin the action in NLA editor.



It will then "un-timeremap" your action and allow you to select with B.

Not sure if "feature or bug", will ask Aligorith or a dev.