I see that a few others have asked this question, but don't see a final resolution when they say your offered solution doesn't work or is incomplete. So, I will ask again. I am currently working with V5 (I know it's older but purchased this software and couldn't get it to work for me on the sites I was building, so went back to Artisteer for a while). Would REALLY like to go forward with TT as i like some of the features, but this is one of the major stumbling blocks. I need to know how to SHOW the main menu on tablet, phone but HIDE on desktop. I tried your suggestion offered to another user:
answered Jan 15, 2015 by sarah (14,600 points)
Please try to use the module class suffix as visible-xs (without dot).
Joomla admin -> Extensions -> Module Manager -> Click over the module on which you want to use class suffix -> Advanced -> Module class suffix -> visible-xs
This process works on custom html modules but not on the menu for some reason. I see that the other user didn't get it to work, told you that, but there was no follow up. If it can't be done, let me know that too so I can find another option for my templates.