Symptoms
In POA 5.5 it was possible to display HTML inside widgets like grids, active elements, etc.
Starting with POA 6.0 HTML is escaped.
Reason
Starting with POA 6.0 widgets escape HTML for security reasons.
If your application needs to render HTML, it can use the aps/Output widget.
In addition to that, aps/Grid in POA 6.0 allows to set the escapeHTML property to false to render HTML in a column.