[Question] Hide calendar from selectable buffers

[Selora]

Hi there,

Thanks a lot for this plugin, love how convenient it is. I was working over my dotfiles config and wondering if anyone had some 'fix' for this little annoyance:

I often use Vimwiki with multiple split buffers, calendar on the side. When selecting previous or next buffers, it often end up with the calendar. Not sure how NERDTree manages to do this.

I know it's probably a 0.5/10 in the priority list and this is 100% nitpicking. I just thought it was the best place to ask.
Thanks!