MIDI Editing Problem [Cubase Pro 11]

Quite suddenly I’m having a problem when moving/deleting notes on a MIDI or Instrument track . . this is happening on all projects.
If I delete an existing note then all other notes following that advance towards the head of the clip by the amount that has been removed. I have not consciously altered any editor settings . . . Can anybody help me with this problem?
Cheers . . . Martin

Hi,

Could you try in the Cubase Safe Start Mode [Disable preferences], please?