Prevent help popup to disappear when clicking on it

Author: GuillaumeGomez

src/librustdoc/html/static/main.js

@@ -380,8 +380,11 @@ function getSearchElement() {
                 set_fragment(cur_id);
             }
         } else if (hasClass(document.getElementById("help"), "hidden") === false) {
-            addClass(document.getElementById("help"), "hidden");
-            removeClass(document.body, "blur");
+            var is_inside_help_popup = document.getElementById("help").contains(ev.target);
+            if (is_inside_help_popup === false) {
+                addClass(document.getElementById("help"), "hidden");
+                removeClass(document.body, "blur");
+            }
         } else {
             // Making a collapsed element visible on onhashchange seems
             // too late