Selecting Over Geometry
The Select over Geometry tool lets you drag a box or lasso over a model without starting the drag from a blank region of the graphics area.
Select over Geometry is helpful when you cannot start the drag from a blank region. For example, use it when the model fills the graphics area or when unwanted items would be included in the selection.
Without Select over Geometry, if you start the drag on top of geometry, the drag fails and the geometry under your initial click is selected:
To select over geometry: