The behaviour as per subject line happens if I call up general settings (Alt+F+T), go to Editor, and click OK.
In the ribbon, the markup setting still displays "no markup", but my target segments show all the track changes. I can fix it by toggling through the "no markup" dropdown.
I can reproduce this behaviour in several projects.
I can reproduce this behaviour in several projects.
Several or all projects?
I ran a quick test in CU1 Beta as I had it open and for me only additions to the text show as markup. Deleted words remain hidden. Is this the same for you?
Paul Filkin | RWS Group
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Paul , yes, the deleted words remain hidden, exactly as you describe.
Sorry for the sloppy writing, I meant I can reproduce this behaviour in all of the several projects I've tested it on. 
Thanks for moving this topic to the CU1 Beta group.
Thanks Emma Goldsmith , we'll follow it through in the Beta since that will address things that need to be changed in the current production version.
Paul Filkin | RWS Group
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You've done the courses and still need to go a little further, or still not clear?
Tell us what you need in our Community Solutions Hub
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