The class list shows only namespaces (I think) and they cant be expanded. The class hierarchy doesnt displays anything, going by the Textual list has most of the links pointing to WeakPtr or SharedPtr. Also, ther eis no way to check class inheritance. the only way I see to actually check a class documentation is via Class members.
Are you referring to the documentation hosted on our website or documentation generated locally for one of the IDE? If it is the former then ensure you are using modern browser that supports SVG and with javascript enabled. If it is the latter then you have to mention for which IDE and in which format because we support a few. In my knowledge the “Urho3D.qch” (Qt format) does not expand/collapse the namespace in the “Class List” page as expected. But other format does not seem to have this issue (at least on Eclipse IDE which I tested). So, the latter could well be a Doxygen’s bug.
The one generated by doxygen.
If the latter then you still haven’t answered my question. We have configured Doxygen to generate the documentation in a few output formats.
The html version, I havent looked at others yet.
If it is the html version then check your browser version and the JavaScript option. It should not be IE6 or something like that 
.