This issue began when i put the icon in the navbar and i turn on the responsive mode on Firefox.
I'm actually not sure whether it's an issue or a bug.
Here's my screenshot :

And the code for the navbar is right here : http://pastebin.com/uhDc94VZ
Any Help appreciated.
That's should be fixed in master #3400
thanks @kmmbvnr , will try it from your pen (http://codepen.io/kmmbvnr/pen/rLPqkQ)
And you mentioning about putting side-nav outside the nav tag ? Like this or not : <ul id="nav-mobile" class="side-nav fixed left-align">
@iqbalaqaba yep, with 0.97.7 you can just move ul outside of <nav></nav>
thanks @kmmbvnr ! it solved the problem and created another problem :confused:
Now the icon is worked perfectly but i can't scroll my side-nav menu when it's on mobile devices.
@iqbalaqaba Can you post a codepen with your menu?
Most helpful comment
@iqbalaqaba yep, with 0.97.7 you can just move
uloutside of<nav></nav>