René J. V. Bertin wrote: >> Always test with Fusion style. If it works there, the bug is in QtCurve. > > FWIW the same thing happens with both Breeze and Oxygen in their Qt4 versions.
For future reference: In the end I got out the debugger and traced the issue into Qt, realising that a style hint was introduced in Qt5 that allows styles to indicate that they render texted separators: SH_Menu_SupportsSections. Returning true for this hint fixes the issue. R.
