Fix visible links test

src/background/tabs.js

@@ -2,9 +2,11 @@ let prevSelTab = 1;
 let currSelTab = 1;
 
 browser.tabs.onActivated.addListener((activeInfo) => {
+  return browser.tabs.query({ currentWindow: true }).then((tabs) => {
     prevSelTab = currSelTab;
     currSelTab = activeInfo.tabId;
   });
+});
 
 const closeTab = (id) => {
   return browser.tabs.remove(id);