I've just given that QT5 version a blast and whaddaya know - the characters are turning up in the order I type them.
Everything seems OK even when using my original SE configuration, although I only gave it a very cursory once-over.
What I notice is that with my large test file open and when typing a sequence of 4 chars that do exist in the file, the search box populates quite quickly, but when typing a 4 char sequence that does not exist, one CPU maxes out for about 5 seconds and then the input box populates with the 4 chars. In both cases they do appear in the correct order though. I suppose the delay is to be expected because there is a lot of data to sift through before concluding that the characters do not exist.
