The pagetree is what you see on the left side, to the right of the menu when you are in any of the web modules.  It's where you see the structure of your site and typically should reflect in your navigation.

How long the pagetitle is before you see the ellipses depends on your user settings, you can have it quite long, the pagetitle in the image below is set at 60, the default is only 30 characters.  This does not affect how long you can actually have the pagetitle, it only affects how much of it you see before the ellipses.

1. Create New page
2. Reload the tree from server (refresh it).  Sometimes if you move from page to page in the list module, the pagetree won't keep up.  So if you have deleted a page in the list module, and it's still in the pagetree, refresh the tree.
3. ? - A brief explanation of what a the pagetree is.
4. Filter
5. The root page of this site.  If you edit several sites, you may have more than one in your pagetree.
6. If there is a + next to a pagetitle, then there are more pages under this page.  Click the + to expand.