Using a FieldLabel causes a GWT warning:
[DEBUG] [gxt_3_0] - Rebinding com.sencha.gxt.theme.base.client.field.FieldLabelDefaultAppearance_FieldLabelTemplate_render_SafeHtml__String_id__Style_style__boolean_isTop__int_labelWidth__int_padding___SafeHtmlTemplates
[DEBUG] [gxt_3_0] - Invoking generator com.google.gwt.safehtml.rebind.SafeHtmlTemplatesGenerator
[TRACE] [gxt_3_0] - Constructing interface com.sencha.gxt.theme.base.client.field.FieldLabelDefaultAppearance_FieldLabelTemplate_render_SafeHtml__String_id__Style_style__boolean_isTop__int_labelWidth__int_padding___SafeHtmlTemplates
[TRACE] [gxt_3_0] - Generating method body for render0()
[WARN] [gxt_3_0] - Template with variable in CSS attribute context: The template code generator cannot guarantee HTML-safety of the template -- please inspect manually or use SafeStyles to specify arguments in a CSS attribute context
[WARN] [gxt_3_0] - Template with variable in CSS attribute context: The template code generator cannot guarantee HTML-safety of the template -- please inspect manually or use SafeStyles to specify arguments in a CSS attribute context
It only appears in the Eclipse GWT "Development Mode" view, but still is quite annoying since I'm using FieldLabels a lot. And here a simple code of course:
Code:
    public void onModuleLoad()
    {

        TextField textField = new TextField();
        FieldLabel fieldLabel = new FieldLabel(textField, "My textfield");

        ContentPanel cp = new ContentPanel();
        cp.setPixelSize(400, 200);
        cp.add(fieldLabel);

        RootLayoutPanel.get().add(cp);
    }
Edit: the error message formattig got kinda lost, so here a screenshot:

FieldLabelWarning.jpg