Validating with tempo.el

[Lennart Borgman]

If templates from tempo.el (or other similar libraries) are used in a 
validating mode like nxml-mode then there may be cases where the prompts 
are overwritten by a message. This occurs in the case of nxml-mode 
because the validation is run with run-with-idle-timer and the message 
is given from within the timer.

I do not know what the best cure for this is. One possible solution is 
adding a variable holding a function to run after something has been 
added by a template. This can perhaps be done with an advice.

Another (more general) solution would perhaps be to

 1) add the message to the message buffer
 2) add it to the beginning of the prompt
 3) redisplay the prompt

Is this possible? Is this desireable?