N°4783 Fix tabs headers hiding on Chrome with zoom-in/out

js/layouts/tab-container/tab-container.js

@@ -157,7 +157,7 @@ $(function()
                 		me._updateExtraTabsList();
 	                }, {
                 		root: $('.ibo-tab-container--tabs-list')[0],
-		                threshold: [1] // Must be completely visible
+		                threshold: [0.9] // N°4783 Should be completely visible, but lowering the threshold prevents a bug in the JS Observer API when the window is zoomed in/out, in which case all items respond as being hidden even when they are not.
 	                });
                 	this.element.find(this.js_selectors.tab_header).each(function(){
 		                oTabsListIntersectObs.observe(this);