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
GridLayout layout = new GridLayout();
        layout.marginHeight = 0;
        layout.marginWidth = 0;
        layout.verticalSpacing = 0;
        layout.horizontalSpacing = 0;
        editorComposite.setLayout(layout);
        createTitleArea(editorComposite);
        Label titleBarSeparator = new Label(editorComposite, SWT.HORIZONTAL
                | SWT.SEPARATOR);
        GridData gd = new GridData(GridData.FILL_HORIZONTAL);
        titleBarSeparator.setLayoutData(gd);
        createInfoArea(editorComposite);
        getSite().getWorkbenchWindow().getWorkbench().getHelpSystem().setHelp(
				editorComposite, IIDEHelpContextIds.WELCOME_EDITOR);
        this.colorListener = new IPropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent event) {
                if (event.getProperty()
                        .equals(JFacePreferences.HYPERLINK_COLOR)) {
                    Color fg = JFaceColors.getHyperlinkText(editorComposite
                            .getDisplay());
                    Iterator links = hyperlinkRanges.iterator();
                    while (links.hasNext()) {
                        StyleRange range = (StyleRange) links.next();
                        range.foreground = fg;
                    }
                }
            }
        };
        JFacePreferences.getPreferenceStore().addPropertyChangeListener(
                this.colorListener);