When you have a custom code block, it does not allow clickable animation edits. I do not know the code off the bat without searching so it would be useful that maybe within a code block, have buttons that you can click to add the code to the block? or maybe a reference menu added somewhere for when using code blocks.
I obviously looked it up and trying to use it within code blocks, but the wow onscroll isn't working currently, could be just me, but if someone knows a good bootstrap code reference site, id appreciate it.
When you use custom code, everything has to be applied manually within the code. The easiest way to add some of the animation functionality would be to add the element to your page you're wanting to add to the custom code. Then copy the settings of the element to the element area you've added to your Custom Code. You may need to just add these settings manually rather than copy/paste since we cannot grab things directly from the code.
It's not a bug, it's how it works. But I would suggest posting a suggestion in the Ideas forum to add the functionality of adding the code itself from elements, into the Custom Code block. Not sure how that could be implemented, but it would definitely be a helpful thing. I'll second it if you want to add it. :)