ExtraWidget* extra = new ExtraWidget( this, true );
connect( extra->prev, SIGNAL( clicked() ), this, SLOT( showPreviousSubMeshes() ) );
connect( extra->next, SIGNAL( clicked() ), this, SLOT( showNextSubMeshes() ) );
ExtraWidget* extra = new ExtraWidget( this, true );
connect( extra->prev, SIGNAL( clicked() ), this, SLOT( showPreviousSubMeshes() ) );
connect( extra->next, SIGNAL( clicked() ), this, SLOT( showNextSubMeshes() ) );