I am creating a custom homepage with a slideshow on top and content (website presentation) below.

When I place printSlideShow before printPageContent, the page content does not show.
When I place printPageContent before printSlideShow, the content appears normally.

Here is the code I use

and

Any errors? Is it really not showing or maybe just overlapped display in whatever theme your are using?

The area where the content is supposed to appear is entirely blank.

No error.

If I place the Slideshow code in a codeblock in a Zenpage, I do get an error:
Notice: Bad gallery in instantiation of album top.alb. in D:\wwwroot\fep\zp-core\class-album.php on line 48

Yes, within the codeblox the $_zp_gallery global is not set/available as it is a call within a function.

You did correctly add the needed js files to the page's ``? Except for the slideshow.php page you need to do that manually.

I will have to try that later myself as that generally should work.

Finally I did get to try this. The reason is that the slideshow changes the context so the page does not work. So after the slideshow call you need to do set_context(ZP_ZENPAGE_PAGE); to restore the page context.