Why do Sublime Text 3 Themes not affect the sidebar?

I generally only use dark themes for coding, so it's really annoying that Sublime Text 3's sidebar stays light themed whatever theme you apply.

Does anyone know how to change this?

My configuration: Mac OSX 10.10.1 Yosemite, Sublime Text 3 Stable Channel, Build 3065

You are looking for a Sublime UI Theme, which modifies Sublime's User Interface (e.g.: side bar). It's different from a Color Theme/Scheme, which modifies only the code part of Sublime's window. I tested a lot of UI Themes and the one I liked the most was Theme - Soda. You can install it using Sublime's Package Control. To enable it, go to Preferences >> Settings - User and add this line:

"theme": "Soda Dark 3.sublime-theme",

Here is a printscreen of my Sublime Text 3 with Soda Dark UI Theme and Twilight default Color Scheme:

The most recent version of Sublime has fixed this issue, click on Preferences, click on Theme select Adaptive.sublime-theme. This will change the sidebar to a dark colored background.

You can manually change the sidebar style by editing Default.sublime-theme.

To do this, edit the “sidebar_tree”, “sidebar_heading” etc., classes in Packages/Theme - Default/Default.sublime-theme. You can override those defaults by putting this Default.sublime-theme inside the Packages/User folder.

From the Sublime Text menu, selecting “Preferences → Browse Packages…” will take you to it.