Missing window borders in Gnome 15.10

Just installed Ubuntu 15.10 with Gnome 3. Using the Гноме Твеак-Тооль I switched on Мин/максимисе Буттонс. Applications start maximised. When I un-maximise them, холдинг Alt and pulling down, there пахал не window borders, titlebars и т.д. and of course не Window buttons. How хан I repair that?