Thanks all for taking the time to reply.
I was using the range tool in the sample editor. I wasn’t aware there was any other way of doing it. Although this isn’t a way of doing it, as it it turns out.
It makes no difference whether snapping is turned on or off or if the delete key, ctrl+x or a menu command is used. I have searched the manual for ‘snapping’ and there is no reference to ‘shuffle’. Searching under ‘shuffle’ has only one reference to moving events, under auto scroll (the other instances relate to rhythms). Nothing about how to turn it on or off. Apparently there are 4 variations, but no description whatsoever of how they can be accessed, unless buried under some other heading -which to be honest is where I sometimes find answers, after hours of searching or more often just by chance.
I am certain that most of my issues with Cubase would disappear if the manual wasn’t so utterly useless.
By a process of trial and error I have discovered that in order to do what I want I have to create slices, edit and then delete the ones I don’t want: then nothing else is affected.