Hi,

Now it seems that we have not allowed to register the callback functions
since beta 2010.02.18.

For example:

\startluacode

local old_pre_linebreak_filter = callback.find ('pre_linebreak_filter')

local function my_pre_linebreak_filter (head, groupcode)
    if old_pre_linebreak_filter then
    old_pre_linebreak_filter (head, groupcode)
    end
    print ('This is my pre_linebreak_callback')
    return true
end

callback.register ('pre_linebreak_filter', my_pre_linebreak_filter)

\stopluacode

\starttext

This is just a test!

\stoptext

The 'my_pre_linebreak_filter' function can not work again. Is this a bug?

-- 
Best regards,

Li Yanrui