Geta Ve is right. WebGL support depends on your graphics card. Some cards don't support all viewing modes unfortunately.
The button in the editor will insert the 'e' for you. Not seeing the button, could be a cache issue... it is located beside the button for inserting an Image.
The button in the editor will insert the 'e' for you. Not seeing the button, could be a cache issue... it is located beside the button for inserting an Image.