Prerequisites: Some tags created in taxonomy

Steps to reproduce:
1. Add ibexa_taxonomy_entry_assignment to a CT (with Product Categories as taxonomy)
2. Create CT from 1.
3. Edit CT
4. Go to meta tab
5. Click on Select product categories button
6. Try to find tag from taxonomy in search window

Actual result:
Tags are displayed in search results for product categories.

Expected result:
Tags should not be displayed in search results for product categories.