https://www.mobileread.com/forums/sh...d.php?t=311992
The issue is apparently fixed in Qt 5.7 and 5.12, but I'm not certain where we left it RE our plan to use Qt5.11.1 in Sigil's next release. I thought there was a conversation about backporting the fix to Qt5.11 but I can't find it, and can't remember the outcome (if there was decision). Perhaps Kevin remembers.
The short answer is "Yeah, we know. Hope to have it fixed/worked-around in Sigil's next release."