4ab4fce998
* Refactor: use pointer down state for alt duplication flag * Refactor: use pointer down state for drag state * Refactor: simplify over scrollbars check * Refactor: move pointer move handler out of pointer down handler * Refactor: move pointer up handler out of pointer down handler * Refactor: further simplify scrollbar check state in pointer down event * Refactor: pull out initial pointer down state creation