Classification with Orange error "test and train datasets have differents target variable"

m having a problem on the widget "Test and score" used for classification. Im doing a classification on images and i would like to use the widget "test and score" with the option "Test on test data".
I used select columns to select the feature "category" as target variable for the two datasets.

The training dataset is ordered in folders (so in class) with 1 image per folder. The feature "category is created by orange using the folder architecture.
For the test dataset the widget "create feature" create the feature "class_name" using a substring of each image and then I create the target variable "category" using the widget "create class". Finaly the feature category is setted as target variable with "select columns" widget.

The two datasets are passed to the "test and score" widget with the option "test on test data"

However I get the error "Test and train dataset have different target variables".
I checked my datasets and i have the same target variable: category.

Error message Test and train dataset have different target variables

Here is the widget "select columns" showing that my two target variable are setted. The variable class_name is a column to drop