"In a dual-display Lister you can now link a tab on the left hand side to one on the right."
Why only in dual mode? I suggest made it possible in single window mode too. Choosing linked tab should activate specific lister (if more than one is open) as destination automatically.
Second suggestion - can you make possible to set one specific lister as destination? No matter what lister I'll select, it always will be source and "forced" destination will not change?
If I put my suggestions in wrong place - I'm sorry.
The only way I could see what you're suggesting be of any practical use would be if you had two monitors - and are basically looking to use two different listers across the two different monitors in exactly the same way as we were looking for this new linked "Tab" feature. But obviously not everyone has dual monitors (though its alot more common than it used to be) so you shouldn't be surprised this wasn't done. I don't see how this would really work in an intuitive way in any case though. I think the best you'll be able to do is use the current LAYOUT features to save a layout with the two listers you want, opened wherever you want them. As soon as you activate that layout the lister that isn't in focus "should" become the current destination... but I know that won't give you selection-specific lister activation AFTER you open such a layout and then start doing ~other work in potentially yet ~other listers...
Only guessing you have dual monitors though... otherwise, I don't see how such a thing would be all that useful to anyone.
We had lock as source/destination/off back in Opus 6 if I remember correctly. It didn't seem that useful and caused a bunch of problems/confusion for people, so it was taken out.
Lock as source/destination/off? Just one lock and just destination (one lister, no more). Source is always source (is obvious, because source is lister what are you using now) but destination is different - in separate listers mode can be confusing sometimes. Simply single lock (just destination) can be really great stuff. And can be useful more than complex lock source/destination etc.
If you lock something as the destination, you can then click on it and run commands in it which won't actually act on that window because some other window is the source. It confused people a lot.