Last modified: 2011-01-25 04:36:13 UTC
[[:en:Help:Category#Category_page]] says : «A category page consists of: (...) list of subcategories; (...) With the Category Tree extension, installed on Wikimedia, one can click "+" to see the subcategories of a selected subcategory».
This is a nice tool to go downwards in the category tree, but a similar tool is needed to climb upwards to the top of the hierarchy.
As clicking step by step to a category several levels higher takes a lot of clicks and a lot of time (one might add : a lot of server resources), such a tool would be useful.
For example, going from [[:en:Snoopy]] to [[:en:Category:Animals]], through [[:en:Category:Fictional dogs]], [[:en:Category:Fictional mammals]], [[:en:Category:Mammals]], [[:en:Category:Vertebrates]], [[Category:Chordates]] requires 6 clicks and 6 calls to the server. With that new tool, you would need only 3 clicks and 2 calls to the server.
I think this new supercategory "+" click should be displayed either near each supercategory link at the bottom of each category page, or next to each subcategory "+" click.
In r36892 I added an inverse mode for navigating the parent categories. It can be activated by setting model="parents" when embedding the category tree. However, this is not yet used with in the category bar at the bottom of pages, as requested, so the bug stays open for now.
In r36949 I have added a highly experimental feature to hijack the category links on all pages and make them expandable inverse category trees. This only works with MW 1.13 r36917 or later and still has massive HTML/CSS layout issues. Compatibility with different browsers and skins is untested, etc. I'll leave the bug open until the fature is ready for prime time though.