IDLE question: "you may still have to reload nested modules."

[alien2utoo at gmail.com]

Hello list,

I am following "Learning Python: Mark Lutz" and came across following in chapter 3
few days back.

[quote]
* You may still have to reload nested modules. Technically speaking, IDLE's
  Run->Run Module menu option always runs the current version of the top-level file
  only; imported files may still need to be interactively reloaded when changed. ...
[/quote]

It is slightly confusing, as to what it does imply. Could any IDLE guru clarify if I am missing or overlooking something?

If a needed-by-top-level-file module was changed after 'Run->Run Module', it would any
way need to be reloaded.

If it was changed between two "Run->Run Module" actions, won't it be automatically loaded afresh as a part of restarting Python interpreter and executing top-level-file [where is the question of reloading then?]?

[Side observation: though F5 or "Run->Run Module" restarts Python interpreter with top-level-file afresh [indicated by dir() content before and after], the command history is not reset during this. This likely confirms the GUI process being separate than interpreter.]

Regards
Sandeep