Shortcut to step back in the block hierarchy in Trackmania Nations Forever's map editor?

In Trackmania Nations Forever's map editor, is there any shortcut to step back in the block hierarchy?

I read on http://bandofscousers.proboards.com/thread/1652/tm2-map-editor-guide :

Besides using the mouse to click on them, you can use the keyboard keys 1-9 to reach them, and the ^ key to make 1 step back in the block hierarchy. Then use the mouse to move around the map, and use the mousewheel to select the desired height to place the part. Alternatively, use the cursor keys and the Scroll up/down keys

However ^ does not seem to work in TMF (the guide was written for TM2).