If you have not tried this give it a whirl. Turn off compatibility view. Next go to settings upper right corner near your login(right past notifications and my profile). So click on settings. On the right hand column scroll down until you see general settings. Click general settings. Then scroll down until you see miscellaneous options. Change the message editor interface to Standard Editor - Extra Formatting controls. Scroll down save the changes. Then go thru and test some items - I know the enter key works for me with that setting, but not the enhanced interface.