These packages make use of gtk3 useflag which indicates that there are issues of migration to gtk+:3. Gtk3 and similar useflags should be avoided. Adding to tracker. Please have a look.
http://wiki.lxde.org/en/LXDE:Questions#Plans_to_migrate_to_GTK3.2B.3F [quote] Plans to migrate to GTK3+? Lubuntu - Plans a migration to GTK3, but LXDE is not yet fully ported to GTK+. So a full GTK+ 3 environment will take some time. [/quote]