Panning: Hold shift key + mouse scroll wheel + move your mouse

Switch between NX windows: hold tab key + click shift as many times as is necessary to get to your desired window

Deselecting selections: Hold shift key + hover the crosshairs over the selected item until it turns from orange to red + left-click

Shortcut to select many items: Hold down left mouse button and highlight the entire model, then release left mouse button

Shortcut to deselect many items: Hold shift key + hold down left mouse button and highlight the entire model, then release left mouse button

Clearing icons in your model such as node numbers: press F5 key