Trigger change event before click
Clarified difference between open and change

Open/Close: apply to the visible image panel
Change: applies to the big image referred to by a thumbnail.
Fix section.js using fix to #3321
Revert "Fix section.js using fix to #3321"

This reverts commit 4a48bb7702cdd9600f8b740bd38c3e50316fc89c.
Fix #3321
move bg-lightness calc to inside adjust test
Merge branch 'Clearing-events'
Merge branch 'sections-fix-#3321'