I took some photoshop lessons in college, I have a hard time grasping the idea of layers and all of that junk, but I am a bit perplexed that, when I have more than one file open, and that top-right area shows me my opened images, that I can't drag that image into my open image, and then have it default to the "Move Selected Pixels" tool and the image be highlighted. Also, the ability to drag them around to rearrange their open order would be appreciated.
That's just my two cents. There's probably an extension that does this.
