Fixed not-scrolling-not-loading bug for MBViewer

public/MBViewer/js/MBViewer.js

@@ -11,6 +11,23 @@
 
 let MbState = {};
 
+// <https://stackoverflow.com/questions/29956338/how-to-accurately-determine-if-an-element-is-scrollable/71170105#71170105>
+function CanScrollEl(el, scrollAxis) {
+    if (0 === el[scrollAxis]) {
+        el[scrollAxis] = 1;
+        if (1 === el[scrollAxis]) {
+            el[scrollAxis] = 0;
+            return true;
+        }
+    } else {
+        return true;
+    }
+    return false;
+}
+function IsScrollableY(el) {
+    return (el.scrollHeight > el.clientHeight) && CanScrollEl(el, 'scrollTop') && ('hidden' !== getComputedStyle(el).overflowY);
+}
+
 function GetDomainFromUrl (url) {
 	return url.split('//')[1].split('/')[0];
 }

public/MBViewer/js/telegram-web.js

@@ -328,6 +328,9 @@ var TWeb = {
 						//$('#BottomAnchor')[0].scrollIntoView();
 						$('.tgme_widget_message_wrap').last().scrollIntoView();
 					}
+					if (!IsScrollableY($('html')[0])) {
+						TWeb.loadMore($('.js-messages_more_wrap > a'), true);
+					}
 				},
 				error: function(data) {
 					var timeout = $moreEl.data('timeout') || 1000;