Until 4.1.3, this was valid:
<table jwcid="table@contrib:Table" columns="User_firstName_colhdg:firstName, User_lastName_colhdg:lastName" ...
The Table component would produce column headings by using "User_firstName_colhdg" and "User_lastName_colhdg" as message keys.
But now, the underscores are replaced by periods (ie. dots) on the fly and the lookup fails, so it outputs these unhappy column headings:
The doco states "the title of the column will be taken from translation strings of the component by using the column id as a key" at http://tapestry.apache.org/tapestry4.1/tapestry-contrib/componentreference/table.html.
A workaround for anyone experiencing this problem is to change all underscores in the affected message keys from underscores to dots - this means throughout your code and in the message properties files. This may of course be quite error-prone in large systems.