Chain layers do not render in annotation frame

[reckart]

It seems that it is possible to create coreference annotations in correction mode, but they are not displayed. The correction (and automation) modes share code with the curation page - and WebAnno presently
does not support the curation of chains. Also, chains would not be supported in the lower part of the correction mode.

However, in principle I believe there is no reason why coreference could not be allowed in the upper frame.