Pop-up windows

An interesting point raised on the IG list - pop-up windows throw people 
out of context. Which is hell for navigation.

DaveP said that his approach was to immediately close them down (my usual 
approach) as the only way to cope with them.

We should add them in section C - they are control devices. I think they 
are a no-no for accessibility (P1) although it could be argued that since 
they are just an annoyance (making everyone equal) and can be shut down 
they are only a P2 no-no.

Charles McCN