[KevinH]

Ah! Native Qt does not support non-contiguos drag and drop reordering with their built-in code.

A quote from a web search:

Qt's default drag-and-drop mechanism doesn't natively support moving disjoint selections. To reorder multiple non-contiguous items, subclass QAbstractItemModel and implement a custom MIME type. Override mimeData() to pack the disjoint indexes, and intercept the drop in dropMimeData() to calculate the shift, removing and re-inserting the items one by one.

So I am not sure supporting it makes much sense.