Unfortunately, neither kdevelop nor kde is something I really want. So I decided to change back to ubuntu. However, things are not that simple by just typing sudo apt-get remove kubuntu-desktop. Extra work should be done to come back. More here

Eclipse is running slowly for the php coding in my five-year old Lenovo notebook. Intending to switch to another IDE, I have found kdevelop which has lead me to the Kubuntu world. Just I did it by opening a terminal and typing sudo apt-get install kubuntu-desktop