Oh I agree cross platform "would" be better, I just don't want to invest the time right now to write that myself
. I was thinking of a quick and dirty plugin to meet my needs...
Plus there is a usability issue. With a separate spawned explorer window, I can happily click to view books in both it and Calibre independently, so I can quickly see for instance if I already have the v5 of an EPUB in my library. Now unless this search window from Calibre was modeless (I guess must be possible, though it raises all sorts of issues) you can't do that.
It was just a random thought. I'm not going to start another big heavy plugin development right now.