Describe the bug
Whatever you pass to the isChildMethod() it always returns true.

Let's say you are in the Starterkit and add the following code in the note.phptemplate:

var_dump($page->isChildOf('notes'));

rightly returns true, but

var_dump($page->isChildOf('photography'));

falsely also returns true.

Expected behavior
The method should create a page object from a string if a string is passed and then compare the parent to that the given page or the page created from the string.

Kirby Version
3.0.0-rc-1