“Select predefined operator” error is encountered when creating substitution mask on row level (4297911)

WORKAROUND
Use some different masking mechanism instead of the predefined operator.

To achieve this please do the following:

1. Click on the “Manage” button in Masks category of the Home tab
2. In the “Manage masks” window make sure the “Substitution” radio button is selected
3. Click on the “New” button  
4. In the “Create substitution mask” window, once name of the mask is provided along with the other desired parameters, from the Type drop-down list choose desired masking mechanism, apart from the “Predefined”

STATUS

Waiting for fix in future release of ApexSQL Mask