We have a number of people who edit or are site owners of either large sites or several small sites. Usually you are only working in one area at a time and not jumping around. And if you have to save your page, it's very annoying to have Typo3 refresh the pagetree, and you loose where you were in the structure.
It's happened to us all I suspect.
But Typo3 provides a way to assist us with this!
To explain I'll use this site as an example. I'm currently working on Workspaces and Versioning. If I have (as I do for this example) several areas expanded, that pushes Workspaces down the pagetree. And on a page save, I'd have to scroll down to find where I was.
I don't want to have to scroll down each time to get back to "Workspaces". So I left click on the page icon next to "Workspaces". I pull down to "More Options..." and choose "Mount as treeroot".
This will remove all other pages than this page and it's subpages from your pagetree. It will keep this even if you log out and log back on. You can cancel it and go back to your full pagetree at any time by clicking"Cancel temporary DB mount" at the top of the pagetree.