This article is part of my personal wiki where I write personal notes while I am learning new technologies. You are welcome to use it for your own learning!
CONTROLlets you move the layer you click on (instead of the selected layer)
- also lets you select an area with multiple layers
ALTand on a layer to duplicate it
SHIFTto keep equal proportions when creating a selection area
CTRL+Tto activate the transformation controls
CTRL+Rto activate the ruler (note that you can drag lines from the ruler into the screen)