The Move tool is used to move layers or selections. Moving layers is a simple procedure. Merely click with Button1 and drag the layer you wish to move. If a layer can be seen underneath the active one, ensure the correct layer is moved. The pointer will by default indicate what will be moved.
The move tool can also be used to "nudge" the current layer in one pixel increments. To do so, select the layer that will be "nudged", focus the image window, and use the arrow keys. Ensure that Numlock is not turned on.
Default Keyboard Shortcut: M
Alt will move any available selection.
Shift will move the currently selected layer regardless of which layer is visible.