There is a memory leak in the QueryForm proportional to the amount of data returned by a query.
The CreateResultsTextBox method in QueryForm.cs deletes the tab pages from the results tab but the datatables used to populate the results grids never get cleared/disposed, and even though they go out of scope GC never collects them.
I was able to plug the leak by clearing the datatables (ie DataTable.Clear) and disposing them followed by GC.Collect to "immediately" release the resources.