How to cancel QuickForm execution wizard?

I often use the QuickForm execution wizard in KNIME Client for testing workflows prior to deployment on the web portal. But one aspect is bugging me...there doesn't seem to be a way to cancel execution from the wizard if the workflow enters a long calculation after the quick form nodes have been performed. Clicking Cancel doesn't work, and the wizard remains modal and blocks access to the workflow design window for the duration of the execution.

This can be particularly frustrating and the only solution I have found is patience! Does anyone else have the same problem, or know of a workaround?