I dont mind getting a vertical scroll bar on my sidebar. However, the horizontal scroll bar can be avoided if there was a way for the sidebar to only use the minimum necessary width when displaying all the contents of the sidebar (auto-expanding and auto-shrinking, when necessary).

Maybe, someone who knows the inner-workings of Sublime Text; may be motivated to do something like this as a plugin.

Not really what you’re looking for but I figured it’s worth mentioning that if you double-click the divider it will auto expand to match the current maximum necessary width.

It would be awesome for the sidebar to auto size itself on mouse over to a width able to show all contents without horizontal scrolling, and returned to previous width on mouse out.
Just a suggestion!

Joao