If I use the Script editor in the Advanced Rename dialog, and try to search for or replace a string like abc (all lower-case) in the Find/Replace dialogs, the string will be saved in the history of them (the drop-down CompoBox).
Now, if I try to search for the string ABC (all upper-case), and once the Find ComboBox loses the focus by tabbing or clicking "Find Next", the dialog will pick the string abc (not considering its case) from the history and use it for search (even if you check "Match case".
The problem here is that if you work with regular expressions, character classes like \d are different from \D, and if you search for one, you'll never be able to search for the other.
Are you using 9.0.0.1? I found a bug like this in 9.0.0.0 that got fixed in the update. Not sure if it was the same thing you're seeing but I can't reproduce what you mention either, so thought I'd check which version you're running.
The bug that I found seems to be a problem with the Windows drop-down control, where it picks a different string from its history if the string you typed is similar (e.g. a prefix). For me it happened when I resized the dialog.
I'm confused now. I thought we were talking about the rename dialog? Which Find dialog do you mean? The two I can think of either don't have a Find Next button (the Find (Search) tool) or don't record a drop-down history list (the text viewer's Find dialog).
Nevermind! I re-read your earlier post while wearing my Enchanted Hat of Reading Comprehension +1 and now I see what you mean. Somehow I totally overlooked the mention of the script editor before now.
I thought we were talking about the rename dialog? Which Find dialog do you mean? The two I can think of either don't have a Find Next button (the Find (Search) tool) or don't record a drop-down history list (the text viewer's Find dialog).