The Path to Root dialog shows the path from the selected object to it's root nodes.
The dialog can also show the paths from it's root nodes to the selected object (the Path from Root).
The data displayed in the right hand window is the source code, for selected entry, the callstack and any related objects.
This is the same information that is displayed in the right hand part of the Heap Dumps view. A more detailed description is provided in that help topic.
•Show Paths to Root Displays the paths from the selected object to the heap dump roots.
•Show Paths from Root Displays the paths from the heap dump roots to the selected object.
•Expand All Expands all paths to/from roots.
•Collapse All Collapses all path to/from roots.