Topic on Extension talk:InputBox/Archive 2

Tracked in Phabricator
Task T381247

Did someone come across this one?

<inputbox>
type=create
prefix=Extra:
preload=Template:PreloadWithCategory
buttonlabel=Create new page
useve=true
</inputbox>

Template:PreloadWithCategory

[[Category:ExtraPage]]

This adds category "Index.php?title=Category:ExtraPage" instead of just "ExtraPage". In other words, it prepends "Index.php?title=Category:" to the intended category name.

I am unsure if this is caused by the default URL schema (https://example.org/index.php?title=PageName, or VisualEditor, or a combination of both. We are talking about MW 1.42 here.