You can hold SHIFT+ESC (as directed in the status bar) to cancel tyFlow's longer operations. Holding is important. It can't simply be pressed and released.
If you've found a place where even holding SHIFT+ESC doesn't stop an operation, let me know and I'll get it fixed.
If you've found a place where even holding SHIFT+ESC doesn't stop an operation, let me know and I'll get it fixed.