If there is one problem that unites the Muslim world in its sympathy it is the Palestinian issue. Forget the republics trying to break away from Russia and the Uighurs of China. They can be ignored just like the Kurds in Turkey, Iran, Iraq and Syria and the Palestinians who reside still as refugees in Lebanon, Syria, Jordan and Egypt.
Forget the many African conflicts such as Darfur, southern Sudan or Somalia. The one problem that will unite Muslims all across the world is the one of Israel and the Palestinians.