SQL Sentry Plan Explorer - missing history?

Previously when using SQL Sentry Plan Explorer, I was able to save the History of queries run in the same session. Now, when I run several queries in succession, save the session, close SQL Sentry Plan Explorer and then reopen it, load the saved session - only the last run query shows up in the history? In the screenshot below, the previous 5 queries are missing. I've lost a bunch of query information lately because of this bug. Having query history is incredibly useful, I can see how the same query is behaving over time as database goes through various changes.