I'm in learning mode - so my aplogies if this is a super-noob question. I'm watching the vids I found here http://wikihelp.autodesk.com/Infrastructure_Modele
Thanks and have a great week.
You need to select the whole "forest" for the slider to appear: this can be achieved by first selecting a tree of the forest by using left-mouse-click and then doing another left-mouse-click on it again (note: don't try it with a double-left-mouse-click!)...
Here's what I'm seeing http://www.screencast.com/t/tLunlpCen
Full-disclosure: I JUST installed this as a trial version and have not registered yet. I don't have the Autodesk BIM 360 installed or anything. Usually that wouldn't be an issue - but you never know what detail will make a difference.