QML files don't get highlighted in the project tree

Steps to reproduce

• Launch Creator, with the left side bar in default configuration ("Projects" on top, "Open Documents" on the bottom)
• Open Qt Source tree including qtdeclarative and examples
• Expand a random example (e.g. quick/draganddrop) in the project tree
• Click on "main.cpp" in the project tree
  => Result: main.cpp is highlighted in both "Projects" and "Open Documents"
  
• Click on a random QML file in "Projects", e.g. "externaldraganddrop.qml"

Expected result

QML file is highlighted in "Projects" and "Open Documents"

Actual result

QML file is highlighted in "Open Documents", but not in "Projects".