Color reset to "black" when click the un-transparent color button in "qt quick toolbar" when edit qml file in .qml editor mode.

Steps:
1. Create a qml file into project. then edit it in qml editor.
2. Open the "qt quick tool bar" by click the light icon beside the "Rectangle".
3. Click the color pane to set color to rectangle border.
4. Click un-transparent color button again

Expect result:
The color of rectangle not change.
Actually result:
The color of rectangle reset to black.