Settle3D > Viewing and Display Options
Within the Plan/3D View you can maximize the Plan View or 3D View, or change the relative size of the views, in various ways:
You can quickly maximize either view by double-clicking in the view.
Double-clicking again in the maximized view, will restore the split-screen presentation.
You can select the following toolbar shortcut buttons - Expand Plan View , Expand 3D View , Split Plan/3D View - to maximize the Plan View, the 3D View, or restore the split-screen format.
You can drag the vertical divider bar at the center of the Plan/3D View to change the relative size of the views.