Screen record button is grayed out in Android Studio

Question

I am using Android Studio 1.2.1.1 on Ubuntu Gnome.The screen capture works fine but the screen record button is grayed out!

I want to know the way to enable the screen record button.

Here is the screen shot:

Answer 1

Fixed it!!

I just had to download my phone's driver.After installing it and connecting my phone,I could take a video of my phone's screen using the screen record button.