I've just submitted the patch to Berlios (#001629), which optionally sets the wxSCI_FIND_POSIX flag on wxScintillas Regex text searches (based on a setting under editor preferences).
AFAICT the only difference is defining groups with ( and ) versus \( and \) - BUT, i use them enough for the difference to annoy me. I put the checkbox in editor settings instead of the find/replace dialog because I figured people will either want one way or the other and not change it each time.
However, I'm still unhappy that wxScintilla doesn't seem to use the wxWidgets advanced style RegExs ("Henry Spencer's"), which support some additional useful wildcard options (such as shortcuts escapes for digits \d, word characters \w, whitespace \s, newlines \n etc), so I may decide to patch my patch...
link:
https://developer.berlios.de/patch/?func=detailpatch&patch_id=1629&group_id=5358
