Re: Rolling display

actually I forgot to explicitly mention when to clear the 
semaphore

On Thu, 1 Mar 2018, R P Herrold wrote:

> then, in the 'document redraw' code, test the 're-draw wanted' 
> semaphore and UNSET the 're-draw wanted' semaphore, 
> remembering the state

and at the appropriate time in that code, 

> and when it WAS set, ... redraw

-- R