The default behaviour of Reaper is to automaticly split all takes at the begining or ending of any new take with a different length.
This happens to become a mess when you have a lot of takes with different lengths, which can happen for several reasons. The most common: an aborted take for some mistake while recording.
There's another way of working which is with the option:
Options > New recording that overlaps existing media items > Creates new media items in separate lanes (layers).
THIS LAYOUT WOULD BE PERFECT, but... it works as layers. And it will only play the TOP layer, unless it's muted... then it plays the next one. This means for working you have to mute every single take or "piece" that you don't want to use, and it becomes complicated to manage this way.
JUST BY ADDING THE OPTION "DON'T AUTO SPLIT TAKES" EVERYTHING WOULD BE MUCH EASIER. You would see every take in a different lane, then you manually split takes where YOU want (All lanes split simultaneously) and then you select the "piece" you want of each take with a single click.
A WAY AROUND TO DO THIS IN CURRENT VERSION:
Put every take file in a different track, then select all tracks, right click and use "Take > Implode Items accross tracks into takes". Then you have all takes unsplit... shorter takes have a "space" where they are empty, and you can manually split the takes as you whish. The downside is that you have to manually assign colors later...
Thanks!
Diego
A link to a thread of people having the same issue:
http://forum.cockos.com/showthread.php?t=108312