Sorry for being slow, but slow is better than a dead project - and CintaNotes by no means is dead yet :) Currently there are 26 ideas which have a higher score, so as you can see, even with an army of developers it would take a while. But you can do something about it - e.g. tell all your friends about CN and get them to vote for this feature!

Why not use the merge command (Ctrl+M)?

Currently it is planned for the Jan-Feb 2014

But there already exists a section selector in the note editor window, or didn't I get the idea?

Released in 2.4

Released in 2.4

Released in 2.4

Will be fixed soon