This dialog box also allows to remove user-defined element templates. In order to do this, simply click on a template in the "Existing element templates" list and then click on the button.
Note that this operation takes immediate effect: clicking on the Save Selected Element As Template" dialog box will not cancel the deletion of the template.button of the "
You can only remove the element templates you have created. You cannot remove predefined (grayed) element templates.
In the above screen shot, notice how removing user-defined "table(simple)" template would restore the predefined template having the same element name and label.
 The button of the "Save Selected Element As Template" dialog box just cancels the action of creating a new template.