Now we can select something on the screen and move it around.
Under the hood, it works like this:
If the user starts dragging a selection, we will do the following:
a. create a new Block shape from the current selection, and put it in Preview mode
b. discard the selected content
When the user drags the mouse, we will update the position of the Block shape
When the user finished dragging, we commit the Block shape to the Grid list
Now we can select something on the screen and move it around.
Under the hood, it works like this: