Disallow imports of parent folder.
fix an issue w/ submitting when the dialog is invalid
Robust fix to stopping infinite imports of parent folder.
fix typo.
review comments
more work on closing dialogs
merge to master; review comments
Merge pull request #2548 from devoncarew/devoncarew_dialog_button

fix an issue w/ submitting when the dialog is invalid
Merge pull request #2522 from dart-lang/disallow_import

Disallow imports of parent folder.
Merge remote-tracking branch 'upstream/master' into resizable-outline-and-better-button
Review: on click between items, find the next adjacent item and select it in otline
Review comments: Outline adds new items to container - not OutlineItems themselves.