How to hide completed tasks in “To-Do-List” step by step:

1. Click “Current view”
2. Manage views
3. Select view and click Modify
4. Click Filter
5. Advanced
6. In “Define more criteria” choose “Frequently used fields” and select “Complete”
7. in condition select “not equal to”
8. in value select “yes”
9. click ok
10. click ok

That’s it!