Wrong initialization of an element with a custom external tool

Scenario

1. On the "External tools" page of the "Application Settings" dialog import the attached custom tool ("My custom tool").
   Expected result: it's added with a warning, because there is no execution path on the computer (note that an invalid tool is used intentionally, so that the validation should not pass in the WD, see below).
2. Create a workflow element "no-run" for this custom tool.
3. Validate the workflow.
   Expected result: the workflow is not valid. There is an error in the WD error list:

   no-run: Custom tool "My custom tool", specified for the "no-run" element, didn't pass validation.
   

4. Restart UGENE.
5. Open the WD.
6. Add "no-run" element to the WD scene and validate it.
   Current result: the workflow validation has passed.
   Expected state: the workflow is not valid. The error described above is shown again.

Possible reason of the problem: when the actor prototypes are created, the external tool registry may be empty.