When number of x cols <= number of layers, use x col as separator to plot into layers; When number of x cols > number of layers, pop up error message: When number of x cols > number of layers, pop up error message. Add X Column" to the "Group By" combo in Multiple Panels by Label tool dialog.

For example, if data is organized as XYYYXYY and user asks for a 2-panel plot, the first three Y columns will be plotted in layer 1, and the last two Y colums will be plotted in layer2.