Error in saving mod-file

Hello everyone,
I have encountered a very simple and strange question when using dynare 4.5.7.
Everytime I open a mod file, edit it, click the ‘save’ button and then try to run the new mod, dynare or matlab still runs the original mod. I try to change the path, but it still does not work. Till now, the only way to solve the problem is to close the present matlab window and reopen it. Does anyone encounter the same problem? Thanks a lot!