Recently, the expansion of the range of users has led to the increase in the importance of software usability. To realize usable software, it is efficient to repeat the process of evaluating and improving GUIs. In this process, it is often necessary to replace the GUI widgets. In this case, we have to change the connection between GUI codes and logic codes. However, it is difficult for developers to find and modify the codes to be changed in the source code. In this research, we propose a method of finding the modification codes in the source code automatically and of suggesting instructions on developers how to modify them.