While digging on how to prevent the user to open the side menu by swiping I found nothing. I tried to override the onEdgeSwipe and onSwipeStart methods of Ext.Viewport but nope...
Some tests after, tadaaa ! If I replace the Ext.Viewport.beforeMenuAnimate method with an empty function it prevent the menu opening by swiping... and by calling Ext.Viewport.showMenu(..)
let oldBeforeMenuAnimate = null;
let noop = function () {};