use own implementaion of alert dialog due to some browsers do not allow to copy a message on system alert()

src/content/mytinytodo.js

@@ -1031,7 +1031,7 @@ function enableFeedKeyInCurList()
         if (curList.feedKey) {
             $('#btnFeedKey').addClass('mtt-item-checked');
             $('#btnShowFeedKey').removeClass('mtt-item-disabled');
-            alert(curList.feedKey);
+            mttAlert(curList.feedKey);
         }
         else {
             $('#btnFeedKey').removeClass('mtt-item-checked');
@@ -1044,7 +1044,7 @@ function showFeedKeyInCurList()
 {
     if (!curList) return false;
     if (curList.feedKey === undefined || curList.feedKey === '') return false;
-    alert(curList.feedKey);
+    mttAlert(curList.feedKey);
 };
 
 
@@ -2652,6 +2652,26 @@ function mttPrompt(msg, defaultValue, callbackOk, callbackCancel)
     }
 }
 
+function mttAlert(msg, callbackOk)
+{
+    $("#btnModalOk").click(function() {
+        $("#modal_overlay, #modal").hide();
+        $("body").css("overflow", "");
+        if (typeof callbackOk === 'function')
+            callbackOk();
+    });
+    var modalOverlay = document.getElementById("modal_overlay");
+    if (!modalOverlay) {
+        modalOverlay = document.createElement("div");
+        modalOverlay.id = "modal_overlay";
+        modalOverlay.style.cssText = "position: absolute; z-index: 999; left: 0; top: 0; width: 100%; height: 100%; background-color: black; opacity: 0.8; display:none;";
+        document.getElementsByTagName('body')[0].appendChild(modalOverlay);
+    }
+    $("#modal .modal-content").text(msg);
+    $("body").css("overflow", "hidden");
+    $("#modal_overlay, #modal").show();
+}
+
 
 /*
  *  History and Hash change

src/content/theme/dark.css

@@ -21,6 +21,7 @@
     --color-btn-default: #fff;
     --color-btn-hover: #444;
     --color-submit: #444;
+    --color-submit-hover: #555;
     --color-row-underlinig: #303030;
     --color-border-default: #555;
     --color-border-focus: #5a8df0;

src/content/theme/style.css

@@ -24,6 +24,7 @@
   --color-btn-default: #000;
   --color-btn-hover: #efefef;
   --color-submit: #eee;
+  --color-submit-hover: #ddd;
   --color-row-underlinig: #dedede;
   --color-border-default: #ccc;
   --color-border-focus: #5a8df0;
@@ -109,7 +110,7 @@ body {
   flex-direction:column;
   align-items:center;
 }
-body, td, th, input, textarea, select {
+body, td, th, input, textarea, select, button {
   font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", /*Roboto,*/ Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
   font-size: 1rem;
 }
@@ -921,6 +922,41 @@ li.mtt-item-hidden { display:none; }
 }
 
 
+#modal {
+  position: absolute;
+  z-index: 1000;
+  left: 50%;
+  top: 50%;
+  transform: translate(-50%, -50%);
+  min-width: 200px;
+  max-width: 1000px; /* same as #mtt */
+  border: 1px solid var(--color-menu-border);
+  background: var(--color-bg);
+  box-shadow: var(--color-popup-shadow);
+  border-radius: 5px;
+  opacity: 1;
+}
+#modal .modal-content {
+  padding: 1.5rem;
+}
+#modal .modal-bottom {
+  border-top: 1px solid var(--color-border-default);
+  text-align: center;
+  padding: 0.8rem;
+}
+#modal .modal-bottom button {
+  min-width: 4rem;
+  padding: 4px 6px;
+  margin: 0 4px;
+  background-color: var(--color-submit);
+  border: 1px solid var(--color-border-default);
+  border-radius: 3px;
+  transition: background-color 0.1s ease-out;
+}
+#modal .modal-bottom button:hover {
+  background-color: var(--color-submit-hover);
+}
+
 /* font for small screens */
 @media only screen and (max-width: 600px),  only screen and (max-height: 600px) {
   html {
@@ -1021,4 +1057,12 @@ li.mtt-item-hidden { display:none; }
     border-radius:14px;
   }
 
+  #modal {
+    width: 90%;
+  }
+  #modal .modal-bottom button {
+    padding: 7px;
+    border-radius:14px;
+  }
+
 } /* end of @media min 600px */

src/includes/lang/en.json

@@ -117,6 +117,7 @@
     "action_delete": "Delete",
     "action_priority": "Priority",
     "action_move": "Move to",
+    "action_ok": "OK",
     "notes": "Notes:",
     "notes_show": "Show",
     "notes_hide": "Hide",

src/includes/lang/ru.json

@@ -117,6 +117,7 @@
     "action_delete": "Удалить",
     "action_priority": "Приоритет",
     "action_move": "Переместить в",
+    "action_ok": "ОК",
     "notes": "Заметки:",
     "notes_show": "Показать",
     "notes_hide": "Скрыть",

src/includes/theme.php

@@ -278,6 +278,13 @@ $().ready(function(){
 </ul>
 </div>
 
+<div id="modal" style="display:none">
+  <div class="modal-content"></div>
+  <div class="modal-bottom">
+    <button id="btnModalOk"><?php _e('action_ok');?></button>
+  </div>
+</div>
+
 </div><!-- end of #mtt -->
 
 <div id="footer">