I was following this tutorial: https://www.youtube.com/watch?v=EmzfaD6IgZ8
and when it got to the point where I need to apply the mask to my 6 frames (png files) of the can, I am unable to adjust how the clip is displayed in the Movie Clip Editor. I can zoom in but I can't click and drag the image left or right to move it to where I want to apply my mask. The person in the video seems to just click and drag. I've tried both LMB and RMB but neither seems to work. I've also tried pressing 'g' before trying to move it and that also didn't work. Lastly, I've checked to see if there were any settings that might "lock" the view in place, but none exist that I see.
For reference, here is a screenshot of what I'm seeing: