In the EndnoteX9 toolbar of the WORD for Mac 2016 application, the “insert citation” tab appears at the foremost left as a first possibility and other options appear only after clicking on the checkmark on the right of the same tab. However, this is not the option I use more frequently, since I prefer to select a citation in my library and choose the “insert selected citation(s)” option after having clicked on the checkmark close to the "Insert citation” tab. The checkmark is small and frequently it happens to click by mistake on the “insert citation” tab that force you to do another procedure.
If the “insert selected citation(s)” options is preferred by other users too, I wonder whether it is possible to make a software change so that the “insert selected citation(s)” option appears as a default in the EndnoteX9 toolbar. Another interesting possibility would be to make a software change that allows users to personalize the Endnote toolbar and choose the most commonly used tabs, a possibility that is given by Microsoft to users that want to personalize other Word toolbars.