Some Shift+Opt keyboard shortcuts do not show up correctly in the QKeySequenceEdit widget with the British keyboard layout

STEPS TO REPRODUCE

1. Build and run the other test app 'qkeysequenceedit-test'.
2. Press Shift-Opt-B.

EXPECTED: The widget reads "Opt Shift B" or similar (with appropriate glyphs)
ACTUAL: The widget reads just "Opt B" instead.

I've tried this with various keys; some work and some don't. Amongst the alphabetical characters, those that don't work include W, E, P, V, B, N and M.