Updated logic of mobile/tablet sizes & scrollbars.

layouts/scripts/toolbar/data-options/DesignPreview.jsx

@@ -130,7 +130,8 @@ export function DesignPreview({previewOption = {widthDimension: 0}}) {
       return 0;
     }
 
-    const scrollbarOffset = 7;
+    // const scrollbarOffset = 7; Looks like browser scrollbar is not included in the width calculation anymore.
+    const scrollbarOffset = 0;
     return window.innerWidth / 2 - previewOption.widthDimension / 2 - scrollbarOffset;
   }