Dispose on OK AND cancel.

nickcolours/src/com/dmdirc/addons/nickcolours/NickColourInputDialog.java

 
     /** Initialises the listeners. */
     private void initListeners() {
-        getOkButton().addActionListener(e -> saveSettings());
+        getOkButton().addActionListener(e -> { saveSettings(); dispose(); });
         getCancelButton().addActionListener(e -> dispose());
     }