The Explode All button will break up all objects into the individual segments that make up the object in Trace.
For example, a Rectangle will be broken up into Four Individual Lines which can be edited separately.
In comparison, the Explode button will break up the selected object into the individual segments that make up the object in Trace.
Explode: Edit Section: Trace
Explode All: Trace
Explode All Button: Trace