Make the scrollpane view transparent in order to be sure to have only the white background set by the custom viewport.

src/net/java/sip/communicator/impl/gui/customcontrols/SCScrollPane.java

@@ -46,6 +46,7 @@ public SCScrollPane()
     public void setViewportView(JComponent view)
     {
         view.setBorder(BorderFactory.createEmptyBorder(3, 3, 3, 3));
+        this.setOpaque(false);
 
         super.setViewportView(view);
     }