Technically it's impossible to wrap <div>'s with <a>'s in the CMS editor, so instead you can add special attributes to <div>:
- data-widget-link-href
- data-widget-link-target (optional)
- data-widget-link-class (optional)
For example setting in the editor these attributes in such way (please use the sidebar for this, there is no need for Source dialog here):
<div data-widget-link-href='http://example.com' data-widget-link-class='cls1' data-widget-link-target='_blank'>...</div>
will convert this <div> into a <a href><div> structure:
<a href='http://example.com' class='cls1' target='_blank'>
<div>...</div>
</a>