When there are multiple scatter plots open, one can plot the selected points from one plot onto another plot by dragging and dropping them. The drag and drop is executed using the left mouse button. Depeding on the state of the target/destination plot one of the following things will happen:
The same effect can also be achieved by using the copy-paste functionality provided in the Edit dropdown menu. The behavior in case of an empty destination plot is the same as explained above. However, in case the destination plot already has some points plotted in it, Paste Selected (Replace) will overwrite the existing plot with the new points while Paste Selected (Add) will merge the points with the points that were already plotted in the destination plot.