This could also be an upstream reversion bug in QtWebEngine. I found
the following list of QtWebEngine fixes in Qt 5.9.2
Note the following entry:
Quote:
[QTBUG-62112] Fixed upside-down rendering in software rendering mode
|
Sigil's Qt is most definitely falling back to software rendering when run in VirtualBox. That's been the case for quite awhile. I can force software rendering on some physical machines to see if I can get the issue to manifest outside of VirtualBox.