src/vs/workbench/contrib/files/browser/views/explorerViewer.ts/FileDragAndDrop/onDragStart
class FileDragAndDrop:	onDragStart(data: IDragAndDropData, originalEvent: DragEvent): void {
		const items = FileDragAndDrop.getStatsFromDragAndDropData(data as ElementsDragAndDropData<ExplorerItem, ExplorerItem[]>, originalEvent);
		if (items && items.length && originalEvent.dataTransfer) {
			// Apply some datatransfer types to allow for dragging the element outside of the application
			this.instantiationService.invokeFunction(accessor => fillEditorsDragData(accessor, items, originalEvent));

			// The only custom data transfer we set from the explorer is a file transfer
			// to be able to DND between multiple code file explorers across windows
			const fileResources = items.filter(s => s.resource.scheme === Schemas.file).map(r => r.resource.fsPath);
			if (fileResources.length) {
				originalEvent.dataTransfer.setData(CodeDataTransfers.FILES, JSON.stringify(fileResources));
			}
		}
	}