Meld 3.18 directory compare does not find differences when there are
Meld fails to see file differences in a directory compare under Ubuntu 18.04. I was comparing compat-wireless-2014-03-31/drivers/net/wireless/ath/ath5k/ and compat-wireless-2017-11-01/drivers/net/wireless/ath/ath5k/ and Meld said there were no differences. I tried from the GUI, and I tried from the command line with both relative and full paths. In all cases Meld found no differences in the directories. People I work with who use Fedora do not have this Meld problem - Meld reports differences between files in those same two directories.
Note - in the Ubuntu Software Manager comments for Meld, someone else has the same issue of directory compares falsely reporting no difference under Ubuntu 18.04. (Roger's comment says "Does not work. Ubuntu 18.04. Check carefully. Says directories are same, even when they contain different numbers of files.")