When you just load the world.map from mapsforge maps and zoom to level 22-24, then it isn't displayed anymore correctly. The problem seems to be the calculation of the insideArea in the DatabaseRenderer and the call to renderContext.canvasRasterer.fillOutsideAreas(Color.TRANSPARENT, insideArea);. In the method fillOutsideAreas there is a cast to int, which may give wrong result if the map has the bounding box of the whole world.

So obviously nobody will just visualize the world map and go to this zoom level, but with nice feature of the MultiMapDataStore it make sense to have the world map and e.g. the germany.map from openandromaps loaded. If you zoom to 22 or larger, then the visualization of the germany.map doesn't work anymore due to this problem.

A user of my app has this problem reported.