Bug 6579 Packages view: can't open MANIFEST.MF of JAR file
1. Drill into a JAR with a manifest file (MANIFEST.MF) in the Packages view. Note: The JAR must be on the build path. 2. Double-click MANIFEST.MF -> nothing happens 3. From the context menu select "Open" -> nothing happens I used ant.jar in org.eclipse.ant.core as my test case.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/EditorUtility.java
return false;
	}
	
	/** 
	 * Tests if a cu is currently shown in an editor
	 * @return the IEditorPart if shown, null if element is not open in an editor
	 */	
	public static IEditorPart isOpenInEditor(Object inputElement) {
		IEditorInput input= null;
		
		try {
			input= getEditorInput(inputElement);
		} catch (JavaModelException x) {
			JavaPlugin.log(x.getStatus());
		}
		
		if (input != null) {
			IWorkbenchPage p= JavaPlugin.getActivePage();
			if (p != null) {
				return p.findEditor(input);
			}
		}
		
		return null;
	}
	
	/**
	 * Opens a Java editor for an element such as <code>IJavaElement</code>, <code>IFile</code>, or <code>IStorage</code>.
	 * The editor is activated by default.
	 * @return the IEditorPart or null if wrong element type or opening failed