When selection mode is enabled, you can control what entity types you are able to select by using the Selection Masks.
To access the Selection Mask/Snap Points dialog box:
You can also access most of the selection masks on the Selection Mask toolbar.
All of the entity types that can be selected are listed in the dialog box. By default, all entity types are enabled for selection. To turn off the ability to select an entity type, click the name of the entity. For example, click Point to turn off the ability to select points in the graphics area. Most of the selection masks are also available on the Selection Mask toolbar.
Color - for this mask you select a color from the list, when this item is on, entities of the selected color can't be selected.
Arcs - contains a list of all of the arcs in the current graphics area. You can select from the list to enable the selection of specific arc sizes. (The sizes that you select in the list are the arc sizes that you can select in the graphics area.)
Check All - turns on all items so that all entity types can be selected.
Uncheck All - turns off all items so that no entity types can be selected. This makes it easier when you only want to turn on a small number of selection masks.
The available snap point types are listed in the dialog box. By default, all snap point types are enabled for selection. To turn off the ability to select a snap point type, click the name of the snap point type. For example, click Arc Center to turn off the ability to select a snap point at the center of an arc.
Existing Point - is any existing snap points.
End of Entity - the snap points at the ends of entities.
Middle of Entity - the entities center snap point.
Arc Center - the snap points at the center of arcs.
Arc Angle Points - the snap point along an arc.
Intersection Point - the snap points at the intersection of entities.
After making any changes in the dialog box, to accept the changes, click OK. To cancel any changes made, click Cancel.