Simple and small !
Admin disabled categories marker provides visual highlighting of the disabled categories on admin categories list page – it’s all what this extension does.
Will be usefull if you have a big amount of categories with frequently changing status.
You need an vQmod extension to install this plugin. You can get it HERE.
Just copy an xml file to vQmod xml folder.
If something goes wrong – you can rename this file like .xml~ (it will disable plugin) and then contact me with your issue.