Index: trunk/src/org/openstreetmap/josm/gui/MapView.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MapView.java	(revision 16665)
+++ trunk/src/org/openstreetmap/josm/gui/MapView.java	(revision 16668)
@@ -459,7 +459,8 @@
             MapViewRectangle clipBounds = getState().getViewArea(g.getClipBounds());
             MapViewGraphics paintGraphics = new MapViewGraphics(this, g, clipBounds);
-
-            if (layer.getOpacity() < 1) {
-                g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, (float) layer.getOpacity()));
+            float opacity = (float) layer.getOpacity();
+
+            if (opacity < 1.0f) {
+                g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, opacity));
             }
             painter.paint(paintGraphics);