fixed GTK styles handling:

1. don't modify the style unless something changed
2. use gtk_widget_modify_style instead of gtk_widget_set_style, the latter is not recommended by GTK+ developers


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27784 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/statbox.cpp

@@ -91,12 +91,6 @@ void wxStaticBox::SetLabel( const wxString &label )
                          m_label.empty() ? (char *)NULL : (const char*) wxGTK_CONV( m_label ) );
 }
 
-void wxStaticBox::ApplyWidgetStyle()
-{
-    SetWidgetStyle();
-    gtk_widget_set_style( m_widget, m_widgetStyle );
-}
-
 // static
 wxVisualAttributes
 wxStaticBox::GetClassDefaultAttributes(wxWindowVariant WXUNUSED(variant))