[KevinH]

Hmm ... in Sigil/src/Tabs/FlowTab.cpp would you please enable the followingdebug output lines by removing the DBG from each and rebuilding.

void FlowTab::EmitUpdatePreviewImmediately()
{
      DBG qDebug() << "FlowTab emiting UpdatePreviewImmediately from EmitUpdatePreviewImmediately";
      emit UpdatePreviewImmediately();
}

void FlowTab::EmitScrollPreviewImmediately()
{
      DBG qDebug() << "FlowTab emiting ScrollPreviewImmediately from EmitScrollPreviewImmediately";
      emit ScrollPreviewImmediately();
}

And let's see if two load signals are being generated by CodeView or if the second is coming from someplace unrelated to CV?

If only one, then we need to search MainWindow.cpp for other signals or calls to UpdatePreview that are being generated someplace else.