“You perfectly understand what I mean.”
I can only go by what you write, incoherent as it may be. And that is one of the things you are well-known for here on FR:
Incoherence. I can’t read your mind, nor can I divine your intent; I can only respond to what you actually say.
“If the UN court decided what no legislation of the original country applies and no vote is required regarding Kosovo then the same applies to Crimea.”
WRONG! The UN said there is nothing under international law that prohibits declarations of independence; thus, national law is operative and determinative on the issue. Serbia’s constitution was silent on secession; thus, there was nothing under Serbian law to prohibit secession and there was nothing under international to prohibit declarations of independence, so the matter falls to the people of the affected area to decide their self-determination.
The Ukrainian constitution DID address secession, and it required that ALL Ukrainian citizens get to vote on the matter, not just those in the affected area. Russia, as you probably already know, vehemently opposed that; and the separatist areas held their own referenda on secession, without all the citizens of Ukraine getting to vote on it, as the Ukrainian constitution required. Thus, the referenda were unconstitutional, and thus illegal.
Your reading is frivolous. Crimea was indeed an autonomous region and under even the Soviet constitution it had to decide on its exit from the USSR independently from Ukraine.
Regarding Yugoslavia, the constitution was amended in the 1980s and Kosovo didn’t have the rights of the republic.
Anyway, all that you have mentioned were the points of the Albanian side but the court decision wasn’t based on them. The main idea was that the right to self-determination is supreme to national processes. Both Yugoslavian and Ukrainian constitutions are meaningless.