If you've attempted to display the complete address of a supplier in the purchase form using the provided code:

<attribute name="widget">res_partner_many2one</attribute>
<attribute name="context">{'show_address': 1, 'show_vat': True}</attribute>

But I am sure you might be wondering why the address is not showing. In order to fix it, you better add the below line too

<attribute name="options">{"always_reload": True}</attribute>

After adding this line, don't forget to upgrade the module. Once the upgrade is complete, you should see the full address displayed correctly.