Sets the colour of the tracker background, that is the colour that sits behind the tracker line.
p.s. this identifier was already available as trackerBgColour() but was never documented. If you happened to use the older spelling you will need to update your code.
Seems to be broken in Cabbage 2.8.52 
Same code in 2.7.14 worked :
Maybe the syntax changed ? Thanks in advance for your help 
It’s trackerBackgroundColour(), tested and still working 
Sorry ! I didn’t read correctly, I updated with trackerBackgroundColour() and now it works again !
Thanks
