Wt

The documentation that Wt provides, while already sometimes fairly big, is still lacking in certain ways.

Some documentation is out of date, and needs to be corrected. This could lead to entries on the forum with questions that could be avoided with more correct documentation.
Similar to the above case is unclear documentation, where people may be confused about how to use a specific thing, and attempting something that is not viable.

Generally the documentation should be extended as well, to include some examples of common usage. The widget gallery already contains some examples, but that doesn't cover all use-cases.
While it isn't possible to have documentation that spans all potential uses, it is a good idea to include limited examples of most common (and thus most "correct") usage.