Changed the method for controlling the visibility of the "#button_zoo…

…m" button bar (event.js)

If we use "slideDown" & "slideUp", then with "display=grid" for the external block, there may be problems,
Perhaps because we also used "display=none" for the button block.

web/skins/classic/views/js/event.js

@@ -1704,12 +1704,14 @@ function initPage() {
       function() {
         //const id = stringToNumber(this.id); //Montage & Watch page
         const id = eventData.MonitorId; // Event page
-        $j('#button_zoom' + id).stop(true, true).slideDown('fast');
+        //$j('#button_zoom' + id).stop(true, true).slideDown('fast');
+        $j('#button_zoom' + id).removeClass('hidden');
       },
       function() {
         //const id = stringToNumber(this.id); //Montage & Watch page
         const id = eventData.MonitorId; // Event page
-        $j('#button_zoom' + id).stop(true, true).slideUp('fast');
+        //$j('#button_zoom' + id).stop(true, true).slideUp('fast');
+        $j('#button_zoom' + id).addClass('hidden');
       }
   );