modules/web/src/main/java/com/sun/webkit/WebPage.java

*** 205,214 ****
--- 205,217 ----
  
      private WCPageBackBuffer backbuffer;
      private List<WCRectangle> dirtyRects = new LinkedList<WCRectangle>();
  
      private void addDirtyRect(WCRectangle toPaint) {
+         if (toPaint.getWidth() <= 0 || toPaint.getHeight() <= 0) {
+             return;
+         }
          for (Iterator<WCRectangle> it = dirtyRects.iterator(); it.hasNext();) {
              WCRectangle rect = it.next();
              // if already covered
              if (rect.contains(toPaint)) {
                  return;
*** 369,383 ****
                      }
                  }
              }
          }
  
!         // Add the dirty (not copied) rect
!         addDirtyRect(new WCRectangle(dx >= 0 ? x : x + w + dx,
!                                      dy >= 0 ? y : y + h + dy,
!                                      dx == 0 ? w : Math.abs(dx),
!                                      dy == 0 ? h : Math.abs(dy)));
      }
  
      // Instances of this class may not be accessed and modified concurrently
      // by multiple threads
      private static final class RenderFrame {
--- 372,386 ----
                      }
                  }
              }
          }
  
!         // Add the dirty (not copied) rects
!         addDirtyRect(new WCRectangle(x, dy >= 0 ? y : y + h + dy,
!                                      w, Math.abs(dy)));
!         addDirtyRect(new WCRectangle(dx >= 0 ? x : x + w + dx, y,
!                                      Math.abs(dx), h - Math.abs(dy)));
      }
  
      // Instances of this class may not be accessed and modified concurrently
      // by multiple threads
      private static final class RenderFrame {