The History pane

Where to find it. History on the rail. Earlier versions appear

after your next change.

How to use it.

• Before ⇄ After flips between your chart now and how it was just
  
  before your last change.
• ‹ Older and Newer › step through the versions; View this
  
  shows any one of them; Back to Current returns to your live
  
  TreeLine.
• Revert to this restores a version, where it is offered. If a
  
  version cannot be restored, the pane says why.
• Clear all earlier versions… removes them, after asking. Your current
  
  TreeLine is kept exactly as it is.

What to expect. A version you are viewing is a picture: nothing in

it can be edited. Printing and downloads always use your current

TreeLine, never a picture you are viewing here.