The WordPress block editor became extremely slow on a site using Toolset Types, especially when editing posts with very large custom taxonomies (some with 1,000+ terms). Actions like opening the media library, selecting a featured image, or interacting with taxonomy fields caused long delays (30–60 seconds), making normal content editing impractical. Disabling Toolset Types restored performance, confirming the issue was related to how large taxonomies were rendered in the editor.
Solution:
The performance issue was resolved by changing large custom taxonomies from checkbox-style (category-like) inputs to tag-style (autocomplete) inputs. Checkbox-style taxonomy UIs attempt to load and render all terms in the editor, which becomes extremely slow with large term counts. Tag-style taxonomies use an autocomplete input instead, dramatically reducing the amount of data loaded in the editor. After switching most taxonomies to the tag-like format, editor performance improved significantly and editing became fast and usable again.
