When an object is fully constrained, all relevant geometric and dimensional constraints are applied to the geometry.
You should always fully constrain geometry in a dynamic block definition that contains constraints to prevent unpredictable behavior during block insertion.
You can identify fully constrained objects with the constrained status mode in the Block Editor. The BCONSTATUSMODE system variable allows you to switch between the constrained status modes. You can also use the ribbon to switch between modes while in the Block Editor.
The constrained geometry is represented with different colors in the Block Editor Settings dialog box.