Messenger™ in Extension (Facebook™ Messenger) is the easiest way to open and use Messenger from your desktop machine (PC, MAC or Linux). Clicking on the toolbar button, renders Messenger in a standalone UI. Moreover, the window is re-sizable to your desired choice and the changes are auto saved to the memory. Note, to start using this App, you need to have a Facebook account. Important Note: Messenger™ in Extension does NOT belong or related to the official Facebook/Messenger website or application in any ways. It is an unofficial app that is developed and maintained independently.