If you note, the dragmath moodle diva suggests some troubleshooting points, and as I recall they suggest posting detailed info. Your post is somewhat obscure in a number of respects I will note that Apple controls release of java for OSX and that anyone using dragmath on OSX should check to make sure their java is the most recent released by Apple. I would check your js log and your java console as well as your moodle and dragmath version. It is unlikely in my opinion that OS would make a difference in operation OS the js responsible for moving the text expression to the editor. If you would like to email to me info I can use to login and test your installation I'd be happy to do so.