Bug 1151732 disappear panels in sidebar after clicking the Pocket sidebar button r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D22198

--HG--
extra : moz-landing-system : lando

toolkit/components/reader/AboutReader.jsm

@@ -951,7 +951,6 @@ AboutReader.prototype = {
       if (!aEvent.isTrusted)
         return;
 
-      aEvent.stopPropagation();
       let btn = aEvent.target;
       callback(btn);
     }, true);