I'm not sure why but using InputBox is breaking things. I didn't realize it until I go to create a Subpage and see how broken it is.
A simple Inputbox, using preload=Template:Characters creates the page Tester. On this page is a slash-removal link to a subpage History.
The goal is when viewing the page Tester, the link will read as History, and take you to Tester/History when clicked.
What happens instead is the link takes you to /History instead. Which is a subpage of nothing. If you try going to Tester/History through the browser address bar, and put PARENTPAGE on that afterwards, it gives you TEMPLATE:PARENTPAGE as a result.
Does anyone know how to fix this? Or will I have to go back to creating pages with the subst template feature instead?