This dialog is opened when you add a new layer on the active plot. If you select Guess, QtiPlot will divide the window in two columns and put the new layer on the right. If you choose Top-Left Corner, QtiPlot will create a new layer with the maximum possible size and locate it on top of existing layers. The new layer contains an empty plotting area. You can subsequently modify the size and position of each layer by selecting it with the layer number buttons and picking the Layer Geometry command from the context menu.