Make background colours of licence tree completely transparent, should make colouring consistant across all platforms

Fixes issue 3700

Change-Id: I170162b64ec3d21ac80f4460a05599728c4bc403
Reviewed-on: http://gerrit.dmdirc.com/816
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

src/com/dmdirc/addons/ui_swing/dialogs/about/LicenceRenderer.java

@@ -24,6 +24,7 @@
 package com.dmdirc.addons.ui_swing.dialogs.about;
 
 import com.dmdirc.plugins.PluginInfo;
+import java.awt.Color;
 
 import java.awt.Component;
 
@@ -52,8 +53,6 @@ public class LicenceRenderer extends DefaultTreeCellRenderer {
         final JLabel label = (JLabel) super.getTreeCellRendererComponent(tree,
                 value, sel, expanded, leaf, row, hasFocus);
         label.setIcon(null);
-        label.setBackground(tree.getBackground());
-        label.setForeground(tree.getForeground());
         label.setOpaque(false);
         if (((DefaultMutableTreeNode) value).getUserObject() instanceof PluginInfo) {
             setText(((PluginInfo) ((DefaultMutableTreeNode) value).getUserObject()).
@@ -61,4 +60,20 @@ public class LicenceRenderer extends DefaultTreeCellRenderer {
         }
         return label;
     }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @return Background colour for non selected nodes
+     */
+    @Override
+    public Color getBackgroundNonSelectionColor() {
+        return null;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public Color getBackground() {
+        return null;
+    } 
 }