Unable to edit some Hedgehog 4 Fade times

I have plotted a dance show on a HH4 and several cues have ended up with no Fade time in the fields. The default fade time is 5 seconds. I am able to edit the fade times in the cues that have a fade time in them using select field and set.
When I select the empty fade time boxes the line border turns red to show it is selected, pressing Set brings up the Time window, I put in 5s, press Enter and nothing goes into the Fade time field. I have not been able to put in a fade time using the Time key on the command line.
Any suggestion please ?
I did not take a note of the operating system version, will do so tonight.