The task must be in the content tab for context to work. There's no workaround for this. However, if the main pain point is that you don't want to see tasks in your content, the best thing to do is to create a second blocks property called tasks in your custom object types. Blocks properties can be toggled closed:

Setup

1. Do a full space export.
2. Open your object type settings
3. Navigate to the property section
4. Click 'Add property'
5. Click 'Blocks'
6. Name it 'Tasks'
7. Ensure this property is underneath the existing blocks property. Click and drag the property by the 6 dots if it is not. You must have two blocks properties. If you delete the one existing blocks property, all your written notes will be deleted in that object type.

Moving existing tasks into this blocks property

Make sure the Tasks block property is toggled open. Cick and drag your existing tasks by the 6 dots to the left of the task into the tasks blocks property.

Adding new tasks

If your tasks blocks property is beneath the main blocks property (where your notes are), then tasks will automatically be appended to that second section.

You can collapse this section once it has been created. This way, your tasks are technically in your content tab so that the context works, but the tasks can be hidden from your view.

FAQs

• I can't add a blocks property to pages, images, weblinks or files
  Correct, this is only possible for your custom object types.