possible fix for #21

common.js

@@ -13,7 +13,8 @@ var prefs = {
   whitelist: [],
   custom: {},
   mode: 'blacklist',
-  color: '#ffa643'
+  color: '#ffa643',
+  cache: true
 };
 chrome.storage.local.get(prefs, ps => {
   Object.assign(prefs, ps);
@@ -188,7 +189,7 @@ function match({url, tabId}) {
 }
 
 var onBeforeSendHeaders = ({tabId, url, requestHeaders, type}) => {
-  if (type === 'main_frame') {
+  if (type === 'main_frame' || prefs.cache === false) {
     cache[tabId] = match({url, tabId});
   }
   if (cache[tabId] === true) {

data/options/index.html

@@ -42,6 +42,9 @@
     <tr>
       <td><textarea id="custom" rows="5" wrap="off"></textarea></td>
     </tr>
+    <tr>
+      <td><label><input type="checkbox" id="cache"> Use caching to improve performance (recommended value is true). Uncheck this option only if you are using the custom mode and also you need the user-agent string to be altered from the provided list on every single request.</label></td>
+    </tr>
     <tr>
       <td><label><input type="checkbox" id="faqs"> Open FAQs page on updates</label></td>
     </tr>

data/options/index.js

@@ -30,6 +30,7 @@ function save() {
 
   chrome.storage.local.set({
     faqs: document.getElementById('faqs').checked,
+    cache: document.getElementById('cache').checked,
     blacklist: prepare(document.getElementById('blacklist').value),
     whitelist: prepare(document.getElementById('whitelist').value),
     custom,
@@ -43,12 +44,14 @@ function save() {
 function restore() {
   chrome.storage.local.get({
     faqs: true,
+    cache: true,
     mode: 'blacklist',
     whitelist: [],
     blacklist: [],
     custom: {}
   }, prefs => {
     document.getElementById('faqs').checked = prefs.faqs;
+    document.getElementById('cache').checked = prefs.cache;
     document.querySelector(`[name="mode"][value="${prefs.mode}"`).checked = true;
     document.getElementById('blacklist').value = prefs.blacklist.join(', ');
     document.getElementById('whitelist').value = prefs.whitelist.join(', ');