It appears that ZE:A member Hwang Kwanghee is jealous of fellow member SiWan's success.

SiWan revealed on the MBC TV program "Radio Star" aired on the 22nd that Kwanghee was very jealous of how popular he had gotten since his starring in the MBC drama "The Sun and the Moon".

MBLAQ's Lee Joon who was also a guest on the episode said, "I am very close with Kwanghee. When I asked him about SiWan's popularity he honestly replied that he was very annoyed and told me not to even talk about him. He was for real. He said it was the end for him as SiWan and Yoon Dongjoon were doing so well".

SiWan continued, "We did two advertisements when we were still in training. We did one with UEE too and he said, 'I can't be in ZE:A anymore since you take up all the attention' so we spent all day and all night reassuring him".

"So I am glad that he became popular first," he continued, causing a big laughter to everyone.

Source