private boolean confirmDelete() {
		String message;
		int messageType;
		if (tableModel.getRowCount() == 1) {
			message = "Deleting the only version will permanently delete the file.\n" +
				"Are you sure you want to continue?";
			messageType = OptionDialog.WARNING_MESSAGE;
		}
		else {
			message = "Are you sure you want to delete the selected version?";
			messageType = OptionDialog.QUESTION_MESSAGE;

		}
		return OptionDialog.showOptionDialog(table, "Delete Version", message, "Delete",
			messageType) == OptionDialog.OPTION_ONE;
	}
Set up the drag and drop stuff.
Ghidra/Framework/Project/src/main/java/ghidra/framework/main/datatree/VersionHistoryPanel.java