Challenge 2: Why Step 4's Profiler Check Is Still Worth Doing — Solution Walkthrough

Why performing Step 4 anyway is still good practice:

Per Chapter 5's own warning box, a symptom can look like it has an
obvious cause while a genuinely different resource is still
contributing, or while the "obvious" cause turns out to be incomplete.
Finding the null-check bug in Step 3 explains why the button appears
to do nothing — but it doesn't, on its own, rule out that a slow
network call or a resource issue might ALSO be present, or that the
same symptom could partly stem from more than one cause at once.

What skipping Step 4 risks specifically:

If a performance-related contributing factor existed alongside the
logic bug, fixing only the null-check issue might leave the bug report
only partially resolved — the button would no longer silently do
nothing, but users might still experience an unexpected delay or
slowdown from an unrelated performance issue nobody checked for,
since the investigation stopped as soon as one plausible cause was
found.

Why this reflects real investigative discipline:

Confirming there's no additional contributing factor, even after
finding a clear and sufficient explanation, is a genuinely different
habit from stopping investigation the moment any plausible cause
appears — the first explanation found isn't always the complete
explanation, and a quick additional check is cheap insurance against
that.

WHY THIS WORKS AS AN ANSWER
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This exercise applies Chapter 5's own "don't assume, check broadly"
caution to a realistic temptation — stopping an investigation as soon
as any plausible cause is found — correctly explaining why one more
confirming check is worth the small extra effort.