On Austria-Hingary

Austria-Hungary was a country where depend on where you ask you can get 10 to 15 different answers on what their nationality is. Ask in Cracow and pretty much everyone would say they are Polish, ask in Zagreb or Split and everyone would say Croat, ask in Vienna or Salzburg and they will say there are Germans. In the whole country no one identified as Austrian.

At first government in Vienna had policy of: it does not matter who you think you are, you are part of Austrian Empire now. Over the course of 19th century nationalist uprisings for independence keep getting bigger and bigger. Poles especially wanted their own country. Czechs, Slovaks and Romanians of Transylvania as well. 

Then when as compromise with Hungarian uprising they became Austria-Hungary, it made things even worse. Poles and Croats all thought that their national names should be added to the name as well and they should be given as much autonomy as Hungarians got.

After that government in Vienna was occasionally thinking of may be reforming all, so that they get more content. However, it was impossible to grant more autonomy to say Romanians in Transylvania because it fell into Hungary jurisdiction, and they would not want to compromise on that.

However, most of time they were thinking of how long we can last until nationalism will tear the country apart from within and all these nationalities will get their independent countries. 

At the end of WWI, when Austrian army was too busy fighting on the frontlines to suppress nationalists, they rose up and capsized the country from within. Allies of WWI were more than willing to grant pretty much every most of these requests for independence, with exception of German-Austria. German-Austria was renamed simply Austria, Allies said that they cannot join into Germany and arbitrated disputed German Bohemia and Sudetenland to Czechoslovakia, but game them Burgenland instead. There were other disputes over the borders.

That German-Austria issue was later raised by Hitler who wished to honor wishes of German Austrian, whom he himself was. Anschluss of Austria itself came without issue, but territories that were given to Czechoslovakia were more sticky issue. However eventually UK and France agree to give them to Germany, possibly because it was on the same grounds, on which they agreed to independence of parts of Austria.