Its fantastic! Puntuado con 5 de 5 estrellas

The zoom in focused sidebar works with Ctrl-- and Ctrl-+ on web pages! It is great!

Esta valoración es de una versión anterior del complemento (0.1.1.1-signed). 

Puntuado con 5 de 5 estrellas

Unfortunately, I'm only amateour, so if my request was wrong, I'm sorry. And I even did not thought that it can be bug... I would appreciate any way allowing to change zoom in sidebar - now when I put focus in sidebar, zoom anyway affects only main page, that is unfocused.
Thank you

Esta valoración es de una versión anterior del complemento (0.1.1.1-signed). 

OK, this is "missing feature". :)
And I wrote about possible implementation from my side (so yes, doesn't work for now).

Anyway, I created an issue: https://github.com/Infocatcher/Sidebars_List/issues/1
Something already work (you can found link to test version on issue page), but a bit buggy in some cases and doesn't work for Ctrl+mouse wheel.

Puntuado con 5 de 5 estrellas

Is it possible to add zoom options to this addon?

Esta valoración es de una versión anterior del complemento (0.1.1.1-signed). 

Zoom page in sidebar?
Anyway, all sidebars are provided by Firefox itself (see "Load this bookmark in the sidebar" checkbox in bookmarks properties) or by another extensions, so this is Firefox bug...

And I only can try to override built-in zoom mechanism to handle focused page – all other ways are too complicated.