The 740 uses a resistive touch screen which can only detect one touch point at a time - the two finger touch gesture only works on tablets & phones. To measure on an iFly Device touch the screen once to get the Quick Info, touch "Nav", "More Options", then "Measure". Now the measure tool will be on the screen - you can touch and drag the end points of the tool to your hearts content. Tap the screen again to remove the measure tool.