How to seperate wagtail image's tags from page's tags?

Suppose we have a wagtail page defined like this:

class PostTag(TaggedItemBase):
    content_object = ParentalKey(
        'PostPage',
        related_name='tagged_items',
        on_delete=models.CASCADE
    )


class PostPage(Page):
    ...
    tags = ClusterTaggableManager(through=PostTag, blank=True)
    ...

    content_panels = Page.content_panels + [
        ...
        FieldPanel('tags')
    ]

When I want to edit tags field on wagtail admin, it suggests not only pages' tags but also images' tags. I want to some how remove images' tags from suggestions.

In my project, pages' tags are not related to image's tags.

To understand the scenario, look at these two pictures:

The first one shows adding river as a tag into one of the images.
The second one shows the tags field on PostPage.

I don't want to see the river tag as a suggestion on page's tags:

Is that possible? If not, Is it possible to remove tags field from wagtail image model?

Solution

You can do this by setting up a custom Tag model that extends from taggit.models.TagBase. This is then handled as a distinct model from the default Tag model used for images and documents.

from django.db import models
from modelcluster.contrib.taggit import ClusterTaggableManager
from modelcluster.fields import ParentalKey
from taggit.models import TagBase, ItemBase

class PostTag(TagBase):
    class Meta:
        verbose_name = "post tag"
        verbose_name_plural = "post tags"


class TaggedPost(ItemBase):
    tag = models.ForeignKey(
        PostTag, related_name="tagged_posts", on_delete=models.CASCADE
    )
    content_object = ParentalKey(
        to='myapp.PostPage',
        on_delete=models.CASCADE,
        related_name='tagged_items'
    )

class PostPage(Page):
    ...
    tags = ClusterTaggableManager(through=TaggedPost, blank=True)

In this example, PostTag is the custom tag model, and TaggedPost is the link table that relates tags to posts (the equivalent of PostTag in your code).