From the post you previously wrote, I guess all doors and windows you use are 3D models you imported in Sweet Home 3D. If you want a hole to be computed automatically at their intersection with a wall, be sure that you checked the Door or window option at the 3rd step of the furniture import wizard. Your problem could also come from magnetism that you deactivated. Activate it again (see help please) and try to move a door to check if it will adjust to the wall better.