Regarding the html mode

Im installed the Elegant themes, but my html short codes cannot preview

Normally the correct html codes is should be like this:
https://www.ecosway4u.com/a_sample/07/2.13.51.png

but my html mode is like that
https://www.ecosway4u.com/a_sample/07/10.27.04.png

so is this the setting problem ?

thanks