How to debug transition in a QML applications

When i read ‘Debugging QML Applications’ the document in Qt5.0.1. There is a paragraph titled ‘Debugging Transitions’ , i confused how to ‘Show Down Animations’? I didn’t found the menu name ‘Show Down Animations’ in ‘Debugging’. Who known how to use thsi function to debug QML application or give me some advices. Thanks very much!