David,
Wow - don't you ever sleep? Or do you have an alarm rigged to your computer; someone posts a message and "rrrrrnnnnniiiiigggg"!! For a minute I thought you were on Canadian time...
I had seen this a number of times in third party downloaded applications, and realized quite quickly that it was a Microsoft bug - lines would scramble but changing focus to another app, then back (ie. redraw done), would restore them. The web is full of anecdotal posts about this. I don't think it actually slipped by Microsoft - I think it was just a "wait and see" type of thing. Everything they create has an expiry date and maybe they just thought it wasn't worth it. Along the same lines, the free HtmlHelp compiler (Help Workshop) has some dandy bugs, most overcomeable (is that a word?). Support for it ceased long ago. My last little project was a library of help commands for AutoIt - I discovered one of the hhctrl.ocx commands that NEVER DID WORK! It is documented, but a Microsoft post says that it doesn't work and "there are no plans for a fix". That one amused me...
As for the fix, I have to say (chest puffed out) that I played with AutoIt and came up with it on my own. In fairness, though, I have found Delphi workarounds that were similar. My little app is an GUI for a command-line program to create iPod audiobooks - not much software out there for the Windows platform. I figured that somehow refresh was the answer, but that it was only necessary after a scroll, so MSDN's reference page listed all the messages, etc. - LVM_REDRAWITEMS and LVN_ENDSCROLL looked useful, and as a time-saving measure (AutoIt is definitely slower than a compiled app), I threw in the top/bottom calculation. After a little tweaking, it worked!
Try:
http://www.codeproject.com/KB/tips/BoxOTricks.aspx for a quick and dirty (similar) approach - #4 at the bottom.
I think many developers use Vista and higher (though the apps run on XP) so they don't see it on their own machine.
BTW - I have been busy on the Help manual; another post should be available in a day or two.
Have a great (long!) day,
Allen