Index: trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 9818)
+++ trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 9819)
@@ -681,7 +681,9 @@
         int visibileTiles = (int) (Math.ceil((double) height / tileSize + 1) * Math.ceil((double) width / tileSize + 1));
         // add 10% for tiles from different zoom levels
-        return (int) Math.ceil(
+        int ret = (int) Math.ceil(
                 Math.pow(2d, ZOOM_OFFSET.get()) * visibileTiles // use offset to decide, how many tiles are visible
                 * 2);
+        Main.info("AbstractTileSourceLayer: estimated visible tiles: {0}, estimated cache size: {1}", visibileTiles, ret);
+        return ret;
     }