There's really no need for the tabs in the VCO control window.
Here's an alternative setup for the VCO that has no tabs, but is still
nice and compact (nb: I also think we should switch the FM
gains to log, because there's a lot more usefulness in the very
low values, but that's another matter).
This patch is just an example - it would also be possible to put
all the sliders in a vertical column but I just liked this one better.
If you don't like it, I'll put it vertically.