Multi Window Side Bar is a free Android utility app developed by DVG Tech Apps. It allows you to easily access your favorite apps and contacts without exiting or minimizing the current screen. The sidebar lays on top of all the mobile screens of apps or games, so you can access it anytime.

The app offers a variety of features including adding a list of favorite apps and contacts to the sidebar tray, a side bar with a control center like Wi-Fi, sound, Bluetooth, torch, flight mode, mobile data, etc. You can also choose from many given default themes within the app for the sidebar. Additionally, there is an option for sidebar positions left or right.

Overall, Multi Window Side Bar is a useful app for those who want quick access to their favorite apps and contacts without interrupting their current screen. It is compatible with Android 4.0 and up and is easy to use.