Similar to a standard rectangular marquee tool found in many drawing packages. This option is available when a 2D plan view is ready to receive input otherwise it will be greyed out. This option can be used with all of the Select tools.
When the command is selected the mouse cursor will change from the usual pointer to a crosshair. Select elements on the drawing area by clicking a point on the screen to begin the process of selection. Draw a rectangular area, shown on the screen by a red outline, by holding down the left mouse button and dragging the cursor to a second point on the screen. Common element types contained within the rectangular area will be highlighted based on which tool is chosen on the Select toolbar. This means that if you have selected the Select Wall button then all of the walls in the rectangular marquee will be highlighted, but if you clicked on the Select Window button then all windows will be highlighted, etc.