Specifies that the setting on the Dimension Style tab of the Options dialog box determines the dimension style. When you set this option, Dimension Style is unavailable.

Lists and applies the available dimension styles. This control is unavailable when Dimension Style Mapping is enabled.

Displays the Center Line & Mark Properties dialog box.

Allows you to set the dimension axis for a center mark. This button is not available unless the Use Dimension Axis option for Orientation is set. When you click the Dimension Axis button, you will not be able to place a center mark until you select a linear element that defines the dimension axis you want.

Sets the orientation of the center mark. You can set the orientation of a center mark to Horizontal/Vertical, to be aligned with the active dimension axis, or to be defined by two points.

Enables selection of all element keypoints and point-on relationships, including midpoints and endpoints of arcs and lines.  When this option is disabled, you can select only the center points of arcs and circles.

Displays the projection lines on a center mark. Projection lines are drawn when you have selected a curved element, such as a circle or arc. If you place a center mark in free space, projection lines are not drawn.