Steps to reproduce:

1. Create a page with a colon in its title, e.g. "Server: Installation"
2. Create one or more child pages below the newly created page.
3. Insert the Children macro into another page in the same space.
4. In the macro properties, use the page created in step 1 as the parent page. Note: the page is corrently found and autocomplete works in the text box.
5. Save or preview the page

Result:
The children macro is rendered with an error message. In german the error message is:
"{untergeordnete Seiten} konnte nicht bearbeitet werden. Seite nicht gefunden:"

Expected result:
The children macro should display the child pages of the page that was created in step 1.