added some event handler null check

SQUASHED: AUTO-COMMIT-src-client-morphic-events.js,AUTO-COMMIT-src-components-tools-lively-container-navbar.js,

src/client/morphic/events.js

@@ -113,6 +113,10 @@ export default class Events {
 
     HTMLElement.prototype.addEventListener = function(type, cb, ...rest) {
         // we cannot just wrapp a callback cb, because callbacks are also used in removeEventListener...
+        if (!cb) {
+          console.warn("addEventListener: registering empty callback for " + type)
+          return
+        }
         var func = cbMap.get(cb) || (function(...args) {
 
           // this becomes dangerous... without COP, we need a global flag

src/components/tools/lively-container-navbar.js

@@ -1022,7 +1022,6 @@ export default class LivelyContainerNavbar extends Morph {
       eaMethodInfo.class = classInfo.name // for later use
       var name = eaMethodInfo.name
       var methodItem = this.createDetailsItem(name)
-      debugger
       if (eaMethodInfo.static) {
         methodItem.insertBefore(<span class="mod">static</span>, methodItem.querySelector("a"))
       }