Recently we’ve added a new code highlighting feature that should make it easier to work with big and complex HTML files, with deep nested tags structure:
Please note that highlighting is only activated when there is more than one tag with the same name in the hierarchy.
By default, only 6 parent tags are highlighted with 6 different colors. You can change the depth to highlight or completely disable the feature in Settings | Editor | Appearance | Enable HTML tag tree highlighting.
Also you can tweak the colors in Settings | Colors & Fonts | HTML.
This feature is very new and we want your opinions. You are welcome to try it in the latest IntelliJ IDEA 10.5 EAP build and let us know what you think.