Basic text manipulation in editor

Hello there,
This is a very simple thing but one I use a lot, many apologies if I’m missing something obvious.

  1. writing in editor (uk academic template)
  2. highlight text in order to pick it up and move it elsewhere on same page.
  3. can’t pick text up and I get a no-entry sign.
  4. have to cut and paste - still possible but takes longer and fiddlier.

Am I missing something?

Much appreciation