chrome.devtools.panels.create("TT's Automatron", "devtool/icon.ico", "devtool/panel.html",
  function(panel) {

    var panelconsole;

    panel.onShown.addListener(function tmp(panel) {

        panel.onShown.removeListener(tmp);
        panelconsole = panel;

        // this works
        chrome.runtime.sendMessage({type:'get-status'}, function(response) {
          panelconsole.write_queue(response.globalstatus);
        });;

        // this does not work - cannot listen to the same messages from popup.js
        // as I do it in background.js
        chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
          alert();
        });
    });
  }
);

// listening to the same messages as in devtools panel
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {

  switch(request.type) {

    alert('This works');

    // recognising different messages
    case "start-tron":
      //  ..some code..
      sendResponse({globalstatus: globalstatus});

      break;
   }
});

chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
  chrome.runtime.sendMessage({type: "start-tron", tabid:tabs[0].id});
});

var port = chrome.runtime.connect({name: 'automatron_console'});
port.onMessage.addListener(function(item) {
    // if reference exists - panel is open
    if (panelconsole) {
      panelconsole.write_log(item);
    }
});