David,
Thank you for reporting this problem.It was introduced for Emmet shortcut support. I have raised a bug for the dev team to fix the conflict.
For now, please go to Window > Preferences > General > Keys, filter for ‘Ctrl+Shift+W’ and change the CodeMix binding to a different one manually.
Apologies for inconvenience caused. Thank you once again for reporting it.
–Swapna
Genuitec Support