If you use a divider in a toolbar, it also becomes a target of the action "Toolbar: press active toolbar button [XX]". Imho, it shouldn't, as it wastes a scarce and valuable resource. A divider should not count as a button. It is perhaps not a bug, strictly speaking, so I have added it to the tracker as a FR for a change to current behaviour.
Example: you have 16 buttons on Toolbar 1, and you use a divider between the first and second group of 8. Now the action "Toolbar: press active toolbar button 16" will target the 15th button, and you can't control the 16th one remotely anymore.
This is especially important if you use toolbar buttons as a workaround to ensure that custom actions etc. with Command ID numbers that are subject to change can still be accessed using a fixed Command ID (e.g. from an OSC control surface).
Since this is also related to the scarcity of actions to trigger toolbar buttons, I'd like to request an increase of the number of toolbar buttons that can be controlled this way from 16 to, let's say 64. That should hopefully be enough even for those lucky owners of *really* large monitors as well? I have more than enough space for more than 16 buttons even when it is taking up only a part of the side of my laptop screen. 16 is *not* enough, in any case.
(And the same goes for the number of parameters that can be controlled this way, see the actions "Adjust track FX parameter [NN]", but that's another subject).
Discussion thread here.