Definitely points to the slider being a better choice for this case then.
Been tinkering with my other code and not tried to get that working yet though 
OK changed it to a Slider and it seems to work, changing the value the BPM is changed when it is dragged.
How can I get a Value Box next to the Slider which displays the value of it? The two need a shared value…
How do I make the pop-up so that I can still click on Renoise’s main interface when it’s open? Is that non-modal?