drawer: Display the content widget when dragging.
Previously:
- drawerOpen is not set when dragging manually
- Widgets using a Loader{} active on drawerOpen || peeking are shown only when clicked or during peeking, not after the drawer is dragged open
This would result in the drawer content now being shown.
Reviewers: mart
Reviewed By: mart
Subscribers: plasma-devel
Tags: Kirigami
Differential Revision: https://phabricator.kde.org/D12819