Challenge 2: Struggling to Hide the Background After Grouping Everything Together — Solution Walkthrough

The answer:

Per this chapter's own warning box, grouping is not the same as
layering. Grouping keeps objects together for selection and
transformation, but it doesn't provide layers' own independent
show/hide/lock control. By putting the background shapes and the main
artwork into one single group instead of separate layers, the
colleague has no way to hide just one part — the group only offers an
all-or-nothing selection unit, not independent visibility control over
its individual pieces.

Why this specific problem happens:

Hiding requires exactly the kind of independent, per-section control
that layers are built for. A group has no equivalent mechanism — it's
built for moving and transforming a bundle of objects together, not
for toggling visibility on part of that bundle while leaving the rest
visible.

What should have happened instead:

Per this chapter's own guidance, the background shapes and the main
artwork should have been placed on separate layers from the start,
each independently show/hide/lock-able through the Layers or Objects
panel, with grouping reserved only for objects that genuinely need to
move and scale together.

WHY THIS WORKS AS AN ANSWER
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This exercise checks that the inability to hide part of a group is
correctly traced back to using a group where separate layers were
actually needed, per this chapter's own explicit warning.