Unexpected reset of VerticalCenterAnchor button in Qt Quick Designer

As a newbie to Qt, I tried to create the Transitions Application using the Qt tutorial "Creating a Qt Quick Application." Step 10, substep 2 in the tutorial did NOT work:
"2. In Layout, select the vertical center anchor button and then the right anchor button..."
The VerticalCenterAnchor can only be selected in combination with the HorizontalCenterAnchor. Selecting any other anchor automatically resets the VerticalCenterAnchor.
Note: this behavior is only with VerticalCenterAnchor. HorizontalCenterAnchor works as expected.
Workaround: If I enter the correct code manually in main.qml, this displays correctly in Qt Quick Designer. Therefore, the problem seems to be a side-effect of clicking the anchor buttons.
I would rate this bug between P3 and P4. P3 because it affects a primary tutorial for learning Qt Quick, but P4 because there is a workaround. BTW, this is my first Qt bug report, so I would appreciate feedback if I can improve the way I submit bugs.