[platform-ui-dev] How can we control same action button from Package Exp

[Sumit Sarkar <sumits@xxxxxxxxxx>]

I  have contributed some actions thru action sets. Like when one ".test" 
file gets selected in Package Explorer, the
button in the Main Tool Bar will get enabled, otherwise it will get 
disabled.

  <extension
        point="org.eclipse.ui.actionSets">
     <actionSet
           label="Test1"
           id="test1">
        <action
              label="Test"
              icon="icons/some.gif"
              tooltip="Test"
              class="<class name>"
              menubarPath="Menu/Separator"
              toolbarPath="Group"
              id="testid"
              enablesFor="1">
              <selection class="org.eclipse.core.resources.IFile" 
name="*.test">
              </selection>
        </action>
     </actionSet>
  </extension>

Now the button gets enabled when I choose a ".test" file, otherwise the 
button gets disabled,

I want the same button gets enabled when I am editing a ".test" file in 
the editor (editor area is active now)
and gets disabled when I am not editing a ".test" file.

How can I do that?

Thanks,
sumit