Bug 117925 [Intro] Misleading exception message in WelcomeEditor.init()
... it says it expects an IFileEditorInput, but it actually checks for WelcomeEditorInput. Suggested patch appended.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/WelcomeEditor.java
/**
     * Returns the intro item or <code>null</code>
     */
    private WelcomeItem getIntroItem() {
        return parser.getIntroItem();
    }
    /**
     * Returns the welcome items
     */
    private WelcomeItem[] getItems() {
        return parser.getItems();
    }
    /* (non-Javadoc)
     * Sets the cursor and selection state for this editor to the passage defined
     * by the given marker.
     * <p>
     * Subclasses may override.  For greater details, see <code>IEditorPart</code>
     * </p>
     *
     * @see IEditorPart
     */
    public void gotoMarker(IMarker marker) {
        
    }
    /* (non-Javadoc)
     * Initializes the editor part with a site and input.
     * <p>
     * Subclasses of <code>EditorPart</code> must implement this method.  Within
     * the implementation subclasses should verify that the input type is acceptable
     * and then save the site and input.  Here is sample code: