Updating the Projects tree after deleting a file outside creator does not work

Steps to reproduce:

• Open/Create a simple project
• open a file inside creator (so that it appears inside the "Open Documents" list)
• delete the file outside of creator using cmdline or any file manager
• choose "Close" when creator asks what to do with the buffer of this file (do not save)

Expected result:

• file should be removed from "Open Documents" as well as from the "Projects" tree

Current result:

• it is removed from "Open Documents" but it is still inside the "Projects" tree (but now without an icon)

See attached screenshot.