Hello,
The Current Channel option in Guide Channels is used to create new channels of two different types and to selet the channel that you want to assign to the selected guides or hairs.
The Current Channel option in Brush Options is used to select the channel you want to paint. However, I can see the list is not automatically updated after you create a new channel, at the moment you have to exit EditGuides and open it again to update this dropdown list, we are looking into this.
We are updating the documentation to reflect the new changes in the options.
Jeordanis Figuereo (Product Designer. EPHERE Inc.)