9.10.2.1 Word Wrapping for Signalling Charts

You cannot set this attribute for signalling chart entities. Their label is always typeset with text.wrap=no exactly as you specify in the source file.

Note that this feature is most useful if you do not use automatic horizontal scaling hscale=auto, since in that case the distance between entities is determined from the size of the labels - and with text.wrap=yes there is no inherent size for most labels. For notes, which float and whose width is not detemined by the spacing of entities, a new width attribute is inserted, which can specify the width of the note making word wrapping meaningful.

You have effective 3 easy way to typeset long labels.

You can some combinations, as well.

ex90_cshex90