Thanks for your report.
Does this happen with any directory with >50 files or with certain directories/drives only?
Well that set me to thinking. (and playing)
It does not happen on every directory with large number of files. I have one directory that had 57 files in it, and when I first opened the directory in the local pane, the program began its slow response and delay, took quite a while to scroll to the bottom, and I got a couple of "Not Responding" messages in the top title bar. I then clicked back to the root and into another directory that had over 200 files in it, and no problem at all scrolling smoothly threw the list. I then went back to the original directory with only 57 files, and everything appeared fine again! when back into the directory with >200 and it bogged again. Not sure if that helps. I can understand how hard it can be to resolve an issue if it is not consistent to some set of rules..