Resolve the custom group drag ghost from
createGroupDragGhostComponent, or undefined when no factory is
configured (the caller then renders the default chip). Returning
undefined is also what happens when this module is absent.
Resolve the app-supplied overlay model for a group drop target via the
dropOverlayModel option, or undefined to keep the target's default.
Optionalgroup: DockviewGroupPanelRender the drop-preview overlay on a group at position (the same
overlay a mouse drag shows) without a live drag. Returns a disposable
that clears it. Used by keyboard docking so keyboard and mouse previews
are identical (single source of truth). Commit the move via the public
api.moveGroupOrPanel({ to: { group, position } }).
Owns the dispatch of the advanced drag-and-drop hooks:
onWillDragPanel,onWillDragGroup,onWillDropandonWillShowOverlay, forwarding each to the host's emitters so the public event shape is unchanged whether or not this module is registered.The service holds no drag state of its own. The gesture is driven by the DnD backends, and the per-group subscriptions live on the component's group lifecycle (so groups created mid-move are not missed).