Doing a regex search in the Find in Files dialog with
an invalid regex for the search string will give you an
error dialog for every file it searches through.
For example, if you do a regex search for the string
when you really meant
(since it's a regex search), and you're searching
through hundreds of files, each of those files will
give you the same error about having an unclosed group
in your regex.
RText should check before starting a regex search
through multiple files to ensure the regular expression