There are several elements that don't work in the Print view. For reasons that they simply wouldn't work on a PDF as it isn't connected to the internet for it to work, or when it is being printed the element wouldn't work. Such as having a video in the publication and in the PDF of the publication, when viewing from the PDF or the printed version the video would not work on a PDF as PDF's aren't connected to the internet and therefore don't collect data for the video to play and for the printed videos obviously don't work on paper.
Videos are disabled during print view because they won't play when viewing from a pdf and wouldn't work altogether when printed on paper. For a video element to work, it needs to be connected to the internet so that the data for the video to be played needs to then be run onto the publication, which isn't possible on a PDF.
Buttons are disabled because buttons are mainly used to link to another element inside of a publication, such as a popup for example. You can't click buttons on a PDF, also with popups not working, along with button redirecting to different things, it simply doesn't work in a PDF viewing environment.
Slideshows are disabled because it physically isn't possible to be able to make select images show one after another in a PDF environment. You may have to take the images from the slideshow and make a word around by making multiple images for this to work in a different way.
Popups are disabled because it isn't possible to used links to groups and layers inside of a PDF. For popups to work, the popup needs to be in a group along with a link to the group, links all together don't work in PDF's along with showing a popup over other content when needed.
Images are disabled because the PDF preview that is generated takes from elements in the desktop view and so adding an image to the print view can become very confusing for the system in terms of where to place other elements around the image.
Similar to images being disabled. Adding a photo collage to print view can become very confusing for when Maglr generates and organizes all the elements from desktop view, it may not be able to calculate if an element goes before or after the collage.
Links to elements, popups/groups for example, simply won't work in a PDF environment. If you have a popup it may be a good idea to ensure that the popup is spread across its own page. The only link that will work in a PDF would be a hyperlink to a website as it is simply a URL linked inside of some text. This would then open a tab with the URL in that tab.