On Wed, Dec 6, 2017 at 3:56 AM, martin rudalics <rudalics@gmx.at> wrote:

> It is frame-bound. I tested display-buffer-in-side-window
> and that did the trick. Thanks. Is set-window-dedicate-p
> also needed or does the side window setup take care of that?

`set-window-dedicated-p' (with a "d") is not needed. Another buffer may
appear in this window if and only if it has been set up to use the same
side and slot.

​Great.

In the doc string for display-buffer-in-side-window, it says: "Unless ‘display-buffer-mark-dedicated’ is non-nil, softly

dedicate the side window used to BUFFER."

No one will know what 'softly dedicate' means.  If it means what you said above, that should be explained in the doc string too.

​

> If you don't want delete-other-windows to delete this window,

> then also add:

>

> (set-window-parameter (selected-window) 'no-delete-other-windows t)

Indeed, see Bug#27999.

​Thanks for the pointer to some of the thinking that went into the design of the side window feature.

It is working well for me in use with the Treemacs package.

Bob