How do I make controls draggable after showing them?

I want to show controller on any point of the screen when the user touches the screen and hide it when user is not touching. The problem with current solution that when I touch the screen now controller is displayed but I can't drag joystick right away. Need to take finger off and hold again to make it work. How to make it work instantly after showing?

Video of the problem - screencast.com/t/vjCwAx3LoX

Thanks in advance!

Here is a similar demo, maybe you could use it:

howtoconstructdemos.com/floating-thumbstick-capx

Thank you! Will try to implement in that way