js: Have the "SoftRight" key open the menu by focussing it

emccpre.js

@@ -530,6 +530,7 @@ function initPuzzle() {
         // Prevent default even if we didn't do anything, as long as this
         // was an interesting key.
         event.preventDefault();
+        event.stopPropagation();
     }
     menuform.addEventListener("keydown", menukey);
 
@@ -558,6 +559,16 @@ function initPuzzle() {
         }
     }, true);
 
+    document.addEventListener("keydown", function(event) {
+        // Key to open the menu on KaiOS.
+        if (event.key == "SoftRight" &&
+            !menuform.contains(document.activeElement)) {
+            menuform.querySelector("li div").focus();
+            event.preventDefault();
+            event.stopPropagation();
+        }
+    }, true);
+
     // Event handler to fake :focus-within on browsers too old for
     // it (like KaiOS 2.5).  Browsers without :focus-within are also
     // too old for focusin/out events, so we have to use focus events