To create an overlay, drag a population from the Workspace into the Layout Editor. Then drag a second population on top of the first one. When an overlay is allowed, you'll see the borders of the chart box of the first population highlighted to signify that it will accept the contents of the drag. Drop the second graph (or more, if dragging multiple populations at once) on top of the original, and an overlay is automatically created.
Overlays may be created for either univariate or bivariate displays.
Offsetting Histogram Overlays
Right-click on any histogram overlay and choose Histograms from the menu. You will be presented with the following options: Offset, Half Offset, Stagger Offset and Overlaid.
Offset: places all histogram on a vertical offset that fills the chart, scaled to avoid overlap.
Half Offset: uses half the amount vertical offset, for taller histograms, which may overlap.
Stagger Offset: this setting creates a psuedo 3-D look and allows you to change the vertical and horizontal offsets. Once stagger is selected, a blue handle (small square) will appear in the right corner. Click and drag to resize the histogram cube to your desired dimensions and offsets levels.
Overlaid: does not offset the histograms vertically. All are drawn on top of each other.
From the Legend you can reorder the sample in an overlay. Click and drag on the rows in the legend to move them up or down. The order of the lines in the legend mirrors the order of the graphs displayed. Moving a graph's name to the top of the list moves the graph to the top of the overlay stack. Dragging the order of the layers will cause the graph to be redrawn, so you can quickly see which layers you want to feature in the top positions. To remove a layer, right-click on a layer name to select Remove Layer.
The legend provides the user interface to edit several aspects of the overlay. Click the mouse once on the legend to select it. Then drag any of the entries in the legend to change their order.
Clicking and drag the mouse on the black square handles of the legend to resize it. Click on the title area to move the legend.
Clicking the mouse in the colored box at the left side of the legend will pop up a rainbow palette, to let you change the colors of the layers in the graph.
