Minor RegEx Bug

I found a minor issue with the RegEx engine for SE. I have the following text that I wanted to match and tag the expression inside the parenthesis: To match this, I entered the following regular expression: This matches the expression just fine, but it doesn't tag the value inside parenthesis for me to use in the replace operation. The following RegEx was used to add the tagged expression: When executing the "Find" operation on this text, I get the following error: This should be pretty easy to dup in the sample application. I used this same RegEx in Visual Studio (both tagged and untagged expressions), and it worked fine.