The Measurement Panel is useful if you need to quickly save data. In the figure below, the text in the buttons are set to a 5.1 surround sound setup just to show an example.
When an unassigned button is clicked, the active measurement is assigned to this button and plotted with the color of the button. The button will then display the color below it and be turned on. If you then turn this button off, the curve will be erased from the plot. But the measurement exists so you can later turn the button on, and the curve will be plotted.
Note: The measurement raw time domain data is saved. Therefore, if the plot type settings are changed, this may change the curve (e.g. if smoothing is turned on). An alternative way of not displaying the curve of a certain button without recalculating the curve, is to set it invisible from the legend list check boxes in the plot. In the figure below, the Left button is set invisible.