Use the scientific method

• 1. Characterize the problem “The popup menu takes 0.5 sec to appear”

• 2. Make a hypothesis (aided by the profiler) “If I don't scan these files, it will appear in 0.2 sec”

• 3. Confirm your hypothesis s/scan_files()/NOP()

• 4. Change one thing at a time

• 5. Fix, test.

• 6. Did you reach your goal?