This dialog is opened when you want to add a new layer on the active plot. If you select Guess, SciDAVis will divide the window in two columns and put the new layer on the right. If you choose Top-Left Corner, SciDAVis will create a new layer with the maximum possible size over the existing layer, this layer contains an empty plot. You can then modify the size and position of each layer by selecting it with the layer number buttons and selecting the Layer Geometry command from the context menu.