When I use the show table widget on a surface layer which has the feature attribute set but not the properties attribute then the table widget sets the properties to an empty dictionary. This causes 2 issues:

1. The features of the surface layer are not shown
2. Other plugins trying to access the features see empty properties although the feature attribute is populated

I believe these lines are the culprit, so maybe we could change the checks to include both the properties and the features attribute? I will make a quick fork and pull request soon