Don't set panelsize to 0

Fixes CLIENT-187

Change-Id: I76136968621b6fb8ebb3057facfbeaf5519a02dd
Reviewed-on: http://gerrit.dmdirc.com/1812
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>

src/com/dmdirc/addons/ui_swing/dialogs/prefs/CategoryPanel.java

@@ -132,8 +132,9 @@ public class CategoryPanel extends JPanel {
             @Override
             public void correctBounds(final ComponentWrapper cw) {
                 if (cw.getComponent() == scrollPane) {
-                    parent.setPanelHeight((int) (scrollPane.getViewport().
-                            getExtentSize().height * 0.95));
+                    int newSize = Math.max(parent.getPanelHeight(),
+                            scrollPane.getViewport().getExtentSize().height);
+                    parent.setPanelHeight((int) (newSize * 0.95));
                 }
             }
         });

src/com/dmdirc/addons/ui_swing/dialogs/prefs/SwingPreferencesDialog.java

@@ -78,9 +78,9 @@ public final class SwingPreferencesDialog extends StandardDialog implements
     /** Manager loading swing worker. */
     private LoggingSwingWorker<PreferencesDialogModel, Void> worker;
     /** Parent window. */
-    private MainFrame parentWindow;
+    private final MainFrame parentWindow;
     /** Panel size. */
-    private int panelSize = 0;
+    private int panelSize = 300;
 
     /**
      * Creates a new instance of SwingPreferencesDialog.