Keyboard shortcut problem/bug

I don't know if it is a bug or a feature, but it is nevertheless annoying.

Let's say I change layer opacity and then click the layer just to deselect the "opacity box", if I now use the keyboard to pick a tool, say "E" for eraser, then Photoshop thinks I want to go to "Edit" in the top menu and so opens that drop-down all over my document. I must then click somewhere to close the menu and then try again, sometimes this doesn't work either.

Has anyone experienced this? Can you recreate it in your program?