Yes, France and Britain agreed to Hitler's annexation of the Sudetenland. They did not agree in Munich to Hitler's later takeover of the rest of Czechoslovakia...but they just stood by and did nothing.
In the Molotov-Ribbentrop pact, the Soviets were active participants in the invasion and partition of Poland. They annexed the eastern part of Poland, territory that Poland never got back after WW2, that territory remaining part of Lithuania, Belarus and Ukraine to this day. Poland did get German territory (parts of East Prussia, West Prussia, Pomerania and Silesia to the west as "compensation."