Fix inline reticles and dialogs for new scrollbars
Summary:
Fixes T7054. Fixes T7049.
- Stop scrolling Differential reticles when the page scrolls.
- Make dialogs aware of multi-panel UI.
Test Plan:
- Dialogs pop up in the right place.
- Inline + scroll now longer leaves the inline in a fixed position.
Reviewers: btrahan, chad
Reviewed By: chad
Subscribers: epriestley
Maniphest Tasks: T7049, T7054
Differential Revision: https://secure.phabricator.com/D11523