The icon for dragmath does not show up on my moodle. I checked with my administrater and the TeX is turned on. I also have Java installed on my computer. I'm not sure what else we need to do to make it appear.
Does the dragmaths button appear for other users of your Moodle or is it just you? If it doesn't appear for anyone then ask your administrator to double check in Settings>Site administration>Plugins>Filters>Manage filters that TeX IS enabled