Adding e.g. "Numberanimation on [property]" to animate some property results to "Behavior type is not supported in a Qt Quick UI form" warning and in Design view gets disabled so it can't be used anymore.

This format is used quite often in QML files to reduce the amount of required code. So instead of:

Text {
  id: text1
  text: qsTr("Text")
  NumberAnimation {
    target: text1
    property: "rotation"
    running: true
    from: 0
    to: 360
    loops: Animation.Infinite
    duration: 2000
  }
}

Just use:

Text {
  text: qsTr("Text")
  NumberAnimation on rotation {
    from: 0
    to: 360
    loops: Animation.Infinite
    duration: 2000
  }
}

From QDS perspective these could also behave similarly, so allow designer view to be used while not runnign animations in the form editor.