Grouping and locking objects
Add an ability to group/ungroup objects so they can be selected and manipulated together.
Add an ability to lock/unlock objects and groups so they won't be selected until you command "Unlock all".
Same as in most vector drawing programs since 1990x!!
It appears that the group/ungroup option is only available for lines, arrows and shapes. It would be very helpful to allow grouping/ungrouping text markup as well (highlighting, etc.).