Hello, try switching the Density to touch in the Customize Firefox menu, it is located at the bottom right -- Next to Themes! If this helped let me know, and mark as solution if it solved your issue.

Thank you, I had tried that. When I touch the icon a square appears round it as though it is going to drag but it does not move.

I have found a solution .

As I have a clip on keyboard and only need to set things up it works from the keyboard. A hand appears and I can easily drag and drop.

Glad you found a solution!