"Alias property" not updated

The icon right of the id property does not get disabled again.

When clicking that icon (ToolTip says: "Toggles whether this item is exported as an alias of the root item"), a line is added to my top-level QML object with id "foobar", saying

property alias foobar: foobar

and the icon turns red.

When clicking that icon again the line is removed from my QML code, but the icon stays red.

Steps to reproduce:

1. Create a new QML project in Creator
2. open design mode
3. Set the id off the top level QML element (Window in my case) to foobar in the property editor
4. Click the icon next to foobar, it will turn red
5. Click the icon again, it will stay red