--- a/devtools/client/debugger/new/panel.js
+++ b/devtools/client/debugger/new/panel.js
@@ -17,16 +17,17 @@ DebuggerPanel.prototype = {
       targetPromise = Promise.resolve(this.toolbox.target);
     }
 
     return targetPromise.then(() => {
       this.panelWin.Debugger.bootstrap({
         threadClient: this.toolbox.threadClient,
         tabTarget: this.toolbox.target
       });
+      this.isReady = true;
       return this;
     });
   },
 
   _store: function() {
     return this.panelWin.Debugger.store;
   },