This will be fixed in the next 10.0.22 version.
DbVisualizer 10.0.22 has just been release with support to ignore any wild card characters in the grid quick search feature. Open Tools->Tool Properties and select General / Grid category and there to the right is the new setting, Support Wildcard in Grid Quick Search.
When I Ctrl+F in a result set and type '?', it matches any character (letter or space) so it finds the first nonblank cell. I was trying to find the string '????', not search with a wildcard. How can I do that?