I never realized, but 1.5 supports \ & / regardless of 'Replace forward slashes with backslashes' setting - at least in some areas.
In particular in file paths, where you can use \ or / or \ and / or even \/ .
Simple filename searches will treat \ and / the same.
Both are treated as path separators.
/ will not match \ when using regex or wildcards.
For regex and wildcards you'll need to enable Tools -> Options -> Search -> Replace forward slashes with backslashes