Rudder

Steps to reproduce:
1. Create custom technique
2. Save it
3. Delete that technique
4. Goto "Configuration Policy -> Directives"

Result:
Deleted technique is visible in "Directive library" tree.

Expected result:
If technique is not being used by any directive it should be deleted from "Directive library" during deletion from "Technique library".

Current workaround:
Delete unused technique from "Settings -> Active Tree".

Proposed solution:
Deletion of technique should trigger action: "Check if technique is being used by any directive - if not , delete technique from directive library".
To keep system coherent, deletion of last directive of technique should trigger action: "Check if technique still exist Technique library - if not , delete technique from directive library".