When you execute the two activities
- Must do Nesting
- Must do Sub-process
You end up in this situation:

This illustrates the difference between placing activities using nesting or sub-process.
Whenever a sub-process is not-pending, it is considered executed. This is the reason the activity Continue Subprocess is enabled while the Continue Nesting is not.
On the other hand, if you execute the two other activities
- Can do Nesting
- Can do Subprocess
you end up in a different situation:

Notice that Include Nesting and Response Nesting are included and pending while Include Subprocess and Response Subprocess is not.
