add your header decoration to the page content instead.
Assistant.setPageHeaderImage
void setPageHeaderImage(gtk.widget.Widget page, gdkpixbuf.pixbuf.Pixbuf pixbuf = null)Sets a header image for page.
Parameters
page | a page of assistant |
pixbuf | the new header image page |
Deprecated
Since GTK+ 3.2, a header is no longer shown;