Warning 'Markup id set on a component that renders its body only' logged after each log-in

Every time a user opens the CMS a warning is logged:

WARN http-nio-8080-exec-2 [Component.internalRenderComponent:2582] Markup id set on a component that renders its body only. Markup id: ide, component id: dialog.
WARN http-nio-8080-exec-2 [Component.internalRenderComponent:2582] Markup id set on a component that renders its body only. Markup id: idf, component id: dialog.

Traced back this warning to a change in PluginPage.java:373:

    replace(new EmptyPanel("dialog").setRenderBodyOnly(true));

and checked that without the setRenderBodyOnly(true) the warning disappears.