I've a mix of file types, and keep them in different folders. When viewing some folders in the Media Browser, perhaps scrolling down a bit, I find a file I want. Sometimes I drag it, sometimes I hit 'import'. But I instantly see the browser window start a complete refresh of that folder - which sometimes takes a few minutes (and I'm on a very fast machine). The folder of JPEGS makes me really crazy, because if I simply import one picture (of 1000), when I do that, the folder view will refresh from the beginning, taking maybe 5 minutes. Makes me a bit crazy(er). Oh, I'm in CS6, iMac, Yosemite, though it's the same after two OS upgrades.