I’ve been working on the Wiki page for jcome’s brand new Preview window:
Can someone explain the purpose of the Erase Rendered Frames button so I can add it to the page? I’m not quite sure what it’s for 
Preview window can be opened all the time even editing the animation. If you render one section, change the animation and re-render, maybe you want to erase the frames to don’t mix frames from previous version of the file before preview the new one.
-G
Even more, you can have multiple previews for the same document with different document status version on each, isnt’ it?
-G
Oh dear, I’m having a job making a simple file that demonstates this - I’m trying to get a preview that is partly from a previous edit and partly the current edit.
EDIT: I still can’t seem to do this - can someone confirm that this works in the latest version?