I think we have found the problem but it appears to be a bug in converting from 1.9 to 2.x.
I created a new 2.4 theme for our site with the name of "wavelength" all lowercase to conform with suggestions on this site. Also, during this transition I found that the older theme had some icons added that we did not have a license for so I did not bring them over to the new theme. The old theme name was "WaveLength".
When our admin/teachers were updating some of the courses with the now missing icons, this somehow causes the front page javascript to break (at least I am assuming that is what creates the formatting for the front page).
The work-around is two-fold. First, if I remove the list of categories from the front page and save the settings, the front page is fixed. Then, I can add back the list of categories and all is well -- until someone else enters the course with the missing icons.
As a 2nd work-around, I created an gif of a broken image and we created a bogus directory Wavelength/pix/t and placed 5 copies of this image, named as the missing icons. That way the images will not be missing and it won't break the front page (assuming there are no other missing icons).
Certainly we can't be the first site to go with a completely different theme upon migrating to version 2.x that could have hit this problem??
Is there any way to find the courses with images pointing back to anything in the old "WaveLength" theme? Or is there a tool to find something like this?
It seems weird to me that a missing icon encountered by user x on their machine will break the formatting for the front page for everyone. Is this a PHP weirdness?
Constance
PS Should I close this topic and open this issue under a different heading? Or should I report this as a bug??