/* CHECKME: don't we need to recalculate everything? after all, our buffer has changed and is likely to be cleared */
gRegion visible_before = root->m_visible_with_childs;
/* CHECKME: don't we need to recalculate everything? after all, our buffer has changed and is likely to be cleared */
gRegion visible_before = root->m_visible_with_childs;