If you don’t first click another editing tool manually after using the Smart transform tool, you lose the mouse reaction in the editor when working further in the upper part of the piano roll editor. If you go back to the lower Veloctity part of the editor, the smart tool that is still active is not marked as active in blue. You have to get back into a normal mouse reaction mode by selecting it again.
Thanks for reporting this, Bertram. I can confirm this behaviour and we’ll address it as soon as we can.