What did pressing Alt do?

For this instruction: 

Then, you can select the ScoreForm, press Alt, and click and drag one of its corner resize handles to make it smaller.

I followed this, but I couldn't tell what pressing Alt did.  What did this particular part do?

  • Nathan Lovato replied

    Pressing Alt resizes relative to the center of the node, while if you release Alt, you'll resize relative to the opposite handle. You can try in your editor to see the difference.

  • H
    HallOfWeasels replied

    Ah, I was just confused while reading it.  I thought I was supposed to just press the key, and not hold it down.  Thanks for the explanation!