I don't see any way to insert the macron "over" a vowel in Zoho Writer.  I can only insert an empty macron at this point, with nothing underneath it. 

 

I need to place a straight horizontal line (a macron) directly above some of the vowels I type, because many of the words I am writing are Classical Latin words which require the macron.

 

Is there a keystroke combination, or any other way, I can accomplish this in Zoho Writer?