Qt Creator crashed when try to change the anchors of an item in qt quick designer.

Steps:
1. Open or new create a qt quick application.
2. Open the main.qml file in designer mode.
3. Add a flickable item to canvas, and then add a rectangle item to flickable.
4. Click "Layout" tab on the properties window and try to edit the anchors of rectangle.

Expected Result:
The item of anchors show according the selection in time and never lead qt creator crash.

Actually Result:
The items of anchors show chaos according the selection. Qt crashed when user operating.

Please see the attached flash. the flash can be opened by Firefox browser.