I'm surprised to see that this request is 6 years old, has 3.8k views (proving this is a demanded feature) !!!! and is not implemented yet !
It is THE missing feature in Sublime Text and it is not even that hard to implement ...
I don't have enough fingers or even limbs on my body to count the outrageous number of posts asking for that feature.
Every new person I ask if they know a way around that, tell me : "Right? Why didn't they do that already? So stupid!"
NONE of the plugins out there are good enough JUST BECAUSE there is no way to implement it as a static, elegant and friendly sidebar.
Such a shame, I'm now looking for an other IDE ...