Problem with the "Edit Citation" command

I’m using Endnote X2 with Word 2007. Until lately everything has been working fine. Yesterday I noticed that when I try opening the " Edit Citation" dialog box by right clicking on a specific citation and then selecting “More…” , the window does not show up and the program just ignores my request. However, for some reason I can alternatively click “Edit citation” on the Endnote toolbar in Word 2007 (under the Citations group). What’s wrong? Any suggestions?

Thank you very much indeed.