When doing a "Show history" on an artefact in a Studio Pro project you are shown a "Progress" bar. But there is no cancel button. Sometimes the retrieve can take a long time because the history is being retrieved from the remote repository and not local storage. There is no Cancel button on that retrieve. So, the only way out is to either wait (which can be a long time depending on external constraints such as network performance) or to kill Studio Pro from the Windows task manager.
A cancel button would be very handy here, and consistent with the Open Project dialog.
Edit: spelling, punctuation