Fill Color: shows the current fill color applied to the rectangle.  Click on the value field to choose a new Color. For a Transparent (unfilled) rectangle click on the value field and select Web | Transparent.

Layer: shows the layer on which the object exists.  Click on the value field to move the object to a new layer.

Line Style group: displays a summary of all the current Line Style values applied to the outline of the rectangle. Read-only.

Arrow Style: shows the current arrow type applied to the object.  Click on the value field to choose a new Arrow Style for the object.

Color: shows the current color of the rectangle's outline.  Click on the value field to choose a new Color for the outline.

Dash Style: shows the current dash style.  Click on the value field to choose a new Dash Style for the object.

Line Width: shows the current line width. Click on the value field to enter a new Line Width.

The Geometry collection deals with the size and shape of the rectangle and here you can enter new values for its Height and Width.

Corner Radii: if corner radius values are 0 the rectangle will have sharp, right-angled corners.  Set Corner Radii values to create a rounded rectangle.

The Shape Information collection is read-only and displays information about the currently selected object(s).