Can I extend the mixer across two workspaces?

I’d like to have the mixer extended over two (or more) workspaces. I use i3wm with one monitor and have ctrl+alt+arrows set up to cycle through active workpsaces.

It’s not clear to me what you mean. If you mean “can the mixer window appear in more than one workspaces” then that’s a window manager question and ardour has nothing to do with it. If you mean “can the mixer window be larger than my monitor and stretch across more than one workspace” then I think the answer is probably no, though you window manager might possibly offer some trick that could make it work.

Try stating what you want to be able to do much more precisely, with examples of how you’d like to work …

At the moment I have i3wm configured so that the Ardour editor appears in workspace 7, the Ardour mixer appears in workspace 8 and plugins appear in workspaces 9 and 10.

I can switch between workspaces with ctrl+alt+arrows.

As channels are added the mixer quickly gets bigger than my monitor in the horizontal direction. I’d like the mixer to be spanned across e.g. workspaces 8 and 9 so that i can switch visible channels with ctrl+alt+arrows.

Either I misunderstand your question or … that’s entirely a window manager issue. You can make the mixer window as large as you like, but you cannot have two mixer windows, so whether or not you can make a very wide window span two workspaces will be determined by your window manager. I use xfwm and I am fairly certain that it does not allow this.

You understand my question. Thanks for clarifying.