[mkgmap-dev] Sea polygon on top

One user of my maps, with an iQue 3600 device, has reported that the maps are displayed with the sea polygon on top of the map. Map is generated with --generate-sea=polygons. In the TYP file sea polygon is defined with drawing order 2 and land polygon with drawing order 3. Other devices don't show this problem. I seem to recall having read that different devices may behave different about map layers priority. Could you confirm this? Is there a way to avoid this problem, other than using --generate-sea=multipolygon