Details on recreating the issue:
You might need to run thru the steps twice in row but with new query (one with ; and one without would do it).
Here are the steps that are taken to crash SQL Optimizer
1) Opened SQL Optimizer
2) Pasted a query into the Query window
3) Clicked 'Show Plan'
4) When the access path showed up, right clicked in the Path window and selected COPY
5) Pasted the access path into a Word doc
6) Went back to SQL Optimizer and clicked 'Run for all Records'
7) It looked like nothing was happening
8) I clicked 'Run for all Records' again
9) SQL Optimizer crashed
Apply new dll attached to this solution. Unzip QExplain2.zip to " C:\Program Files\Common Files\Quest Shared" and replace current QExplain2.dll.
SQL Optimizer version is 22.214.171.124