Pretty simple, the .grid-stack>.grid-stack-item>.ui-resizable-sw class has bottom: 0 whilst the -se variant has no constraint. Imo it is negatively eye-catching that the sw variant has a left margin but no bottom margin. Would it not make sense to have them the same?

Existing code

> .ui-resizable-se { cursor: se-resize; width: 20px; height: 20px;}
...
> .ui-resizable-sw { cursor: sw-resize; width: 20px; height: 20px; bottom: 0; }

Proposed

> .ui-resizable-se { cursor: se-resize; width: 20px; height: 20px;}
...
> .ui-resizable-sw { cursor: sw-resize; width: 20px; height: 20px;}

The code is here

Example: