TTMSFNCTreeView Drag and Drop with Dropmarks

I use the Virtual Treeview component for my VCL application. It supports drag-n-drop multiple nodes while showing a dropmark which indicates where (above, below, or on a node) the nodes will be placed. It uses a DetermineDropMode event. During the drag-n-drop operation, one can decide to either move or copy (with CTRL) the selected nodes.

I need the same for my FMX application which relies on TTMSFNCTreeView. So I need the user to be able to move or copy multiple nodes while visually showing (with a dropmark) where the selection will be placed. How can this be done?


Right now you can enable internal reordering with Interaction.Reorder. However this doesn't show a drop-target. Alternatively you can implement your own drag & drop mechanism by implementing OnCustomDragDrop, OnCustomDragOver.