There are various editing operations that can be performed on measurements. See also Taking Measurements for information on moving and rotating the width of the measurement.
Deletion
Deletion of one or more measurements can be done by selecting the desired measurements, and then hitting either the Delete key or using the menu item .
IMPORTANT: The current tool (mode) must be the measurement tool 
for deletion to occur.
Example:
1) Measurements to be deleted have been selected using the measurement tool. See image below.
2) With the measurement tool active, press the Delete key and the measurements are removed. See image below.
TIP: To delete all measurements, select from the main menu. You can also accomplish this by using the key combination X+M. Deletion of all the measurements will occur no matter what tool is active.
Changing Radii
You may also choose to increase or decrease the radius of the current active measurement (by 5% of its current size). This can be accomplished by using the + or - keys. Note that the current active measurement is displayed with a circular radius.
- + is used to increase radii.
- - is used to decrease radii.
IMPORTANT: The current tool must be the measurement tool
to be able to change the radius.