Why did the Italians feel that they had been deceived by the Treaty of Versailles?

Italy joined the Allies in the First World War and by the Secret Treaty of London (1915). She hoped to gain Trentino, Trieste, Istria, Fiume, Coastal Regions of Dalmatia, Albania and some parts of Turkey and Germany. But by the Treaty of Versailles she could get only Southern Tyrol and Trentino, and the Coastal Regions of Dalmatia. She could get no part of the German and Turkish colonial empire. The Italians felt as if they had been deceived and thought that their right demands were ignored. Imperialist designs of Italy were completely ignored.