You must declare your action in your layer.xml file. Like this:

<folder name="Editors">
 <folder name="text">
   <folder name="x-java">
      <folder name="Popup">
         <file name="org-mymodule-MyAction.instance"/>
      </folder>
   </folder>
 </folder>
</folder>

Prior to NB 4.2, you could use Editors/text/base/Popup/ to add an action to all editor kits. As of NB 4.2, use just Editors/Popup/ instead.

Source: NetBeans FAQ

 Related Tips

• I have written a module. Can I sell it?
• 2D texture font - NeHe Tutorial JOGL Port
• 3D Human Animation Applet
• 3D lens flare with occlusion testing - NeHe Tutorial JOGL Port
• 3D shapes - NeHe Tutorial JOGL Port
• A model with a light which is moved by a modeling transformation
• A Morph object to animate a shape between two key shapes
• A red sphere using the Sphere utility class