I used unofficial world editor MCC tool chest Pe to regenerate some chunks, because I wanted to see new terrain in my world. I delete chunks that I wanted to regenerate, but they did not. They just disaappeared and now there is just a hole into nowhere. I already used MCC tool before to regenerate world and it worked. I do not know what changed. I am even not sure if it is problem of the game or editor, but I would be happy for any opinion or idea. 

PS: I already found out that there is no other possibility for me to use different editor... I sent hours by searching for other options..