Fix template widget usage in table layout

1) create a tab layout with attached empty widget (see the xhtml file)

2) create a content view using the tab layout

3) create a folder type document using the tab view

Please see steps 1 to 8 for details (screenshots) on how to set up the test case.

4) To reproduce the issue, create a document in the configured folder and see the content view result.
The column name is not the expected one and moreover the available columns list the correct names (see issue1 and issue2)

5) Then you can try to add the B colonne to get both A and but it fails (see issue3 and issue 4).

6) Please note the issue does not happen when not using table layout and for example having results columns directly in a content view.