Note: I edited your post, using the HTML editor to remove the <pre> </pre> tags that were keeping the text from wrapping correctly.
I've also looked at the Relationships diagram and I can't locate any references to Notes.
There's a table occurrence there called "Contact_RelatedNotes"
It has this relationship:
Contacts::K_ID_Contact = Contact_RelatedNotes::K_ID_Contact
The "Tasks Tab" is really a Tasks Layout--designed to look like a tab panel, but you actually click buttons to change layouts instead of clicking tabs in an actual tab control.
It's based on a different table occurrence: Tasks
This creates several problems for you:
1) You'd need to add an occurrence of Notes to Manage | Database | Relationships and link it to Tasks in a Relationship
2) A Task can be linked to any number of different Contacts. The current Notes table is used to make Notes about a specific contact. A Note on the tasks layout could then link to any number of different contacts
Thus, you might consider using the Tables tab in Manage | database to define a new table, TaskNotes so that these notes are separate from your contact notes given the different relationships involved.