Perhaps this is an issue for individual plug-ins.
When I type a command in FARR, using a plug-in,
that generates a large list, FARR goes 'non-responsive'
until the list is completed.
Recently I was using FARR and mru, and I 'accidentally'
typed: mrua instead of mrul
This (mrua) took a few minutes (seemed longer) to
complete but there was no way (that I found) to
interrupt it, or edit the command.
Your are right, this is plugin related. FARR MRU currently collects the results synchronously, although FARR would offer plugins the possibility to do that asynchronously. I didn't do that yet because doing it synchronously is just more straight forward (for implementing, I mean).
I understand your problem though, as I've had it myself. I'm storing all my files on a NAS, which makes everything file related kind of slow. I've tried to cover this problem with FARR MRU's settings, specifically the settings that allow disabling certain file checks for network files. Making the search asynchronous would not speed up anything it would just give the possibility to make the search abortable, which I agree would be very desirable. So I guess I'll think about changing that.
Happy to hear that you're using FARR MRU though
(or at least try using it).