Backed out changeset 59456fe10bea (bug 1561650) for chrome failures at toolkit/content/tests/chrome/test_tree.xul on a CLOSED TREE

toolkit/content/widgets/tree.js

@@ -806,15 +806,6 @@
       );
 
       this.addEventListener("keydown", event => {
-        if (
-          event.altKey ||
-          event.getModifierState("Accel") ||
-          event.metaKey ||
-          event.ctrlKey
-        ) {
-          return;
-        }
-
         switch (event.keyCode) {
           case KeyEvent.DOM_VK_RETURN: {
             if (this._handleEnter(event)) {