Is there a way to see if a GUI is still moving to its position?

I've tweened a frame in the GUI, but I don't want the GUI to let someone be able to use any of the other functions while the frame's still tweening to its destined position. Will I be able to check if it's still tweening?

If it's the "override" part in TweenPosition, I'm confused on what that does and what true/false means in that.

And I apologize if this isn't that clear, I don't know any other way to put it. If you don't understand something I'll happily clarify it.

Thanks in advance!