I got a fix from a reply on another forum.

Apparently the Slate theme already includes the fancybox lightbox in its code, so any other add-on that I try that has the fancybox will fail because the theme and the add-on's copy of fancybox will conflict with each other.

The solution for Sortable Fancybox Gallery was to modify the following file on my server:
[code]
SITEROOT/packages/sortable_fancybox_gallery/blocks/sortable_fancybox_gallery/controller.php
[/code]
... and remove the following code (should be lines #14-22):
[code]
public function on_page_view() {
if ($this->enableLightbox) {
$html = Loader::helper('html');
$bv = new BlockView();
$bv->setBlockObject($this->getBlockObject());
$this->addHeaderItem($html->css($bv->getBlockURL() . '/fancybox/jquery.fancybox-1.3.1.css'));
$this->addHeaderItem($html->javascript($bv->getBlockURL() . '/fancybox/jquery.fancybox-1.3.1.pack.js'));
}
}
[/code]

This worked great but shouldn't be necessary. Is there some way you can provide a warning or an option for users of this theme to turn the theme's fancybox on/off?

Yeah, your probably the third person now that's brought that to my attention and your 'fix' is what I've recommended to the others.

I am going to add this to my to do list for the next update of Slate.

I have just purchased your Bundle, specifically for Slate. It does not seem as if this update has been done yet, and I am creating some Gallery rich sites. Do you have a timescale for this fix?

This issue probably wont be fixed anytime soon. The issue is because both the Slate theme and the gallery addon mentioned above both include Fancybox and they conflict with each other. Me and JordanLev (developer of the mentioned gallery addon) are both aware of the problem and the fix mentioned above is the best solution until concrete5 core comes out with a way to check if a js library is already installed/in use.

Can you perhaps provide an option to deactivate it from the front end instead of editing the code?

Unfortunately that's the only way to fix it for now. We're waiting on a update for concrete5 that will resolve this once and for all.

Perfect. Thanks!