[TYPO3] constant editor doesn't work for goof_fotoboek?

[Bing Du]

Hi,

Typo3 V4.0.4
goof_fotoboek 1.7.11

I made some changes on the goof_fotoboek configurations in the constant
editor.  However, no changes took effect.  For instance, I changed
thumb_per_row from the default 6 to 10 and clicked 'Update'.  Also I
cleared all cache.  But the page still shows 11 thumbs per row.  I didn't
understand where that number 11 came from.  It's neither the default nor
the number I set.  The navigation at the top just has 'previous' and
'next' blue arrows visible.  The two icons in the middle grays out.  Also
I enabled slideshow in the constant editor but I don't see any slide show
icon on the page.

I've ever used constant editor to change other extensions' settings but
never seen such a problem.  What did I miss?

Thanks in advance,

Bing