The main window (except decors) is all black without this (not even hover over toolbar buttons work)

The main window would not refresh at all. A call to this function or adjustSize() seems to fix this

Member BtBookshelfDockWidget::BtBookshelfDockWidget (QWidget *parent=nullptr, Qt::WindowFlags f=Qt::WindowFlags())

The correct grouping action is not selected on startup.

Member BtBookshelfTreeModel::addModule (CSwordModuleInfo &module, bool checked)

Calling reset() shouldn't be necessary here, but omitting it will will break things like switching to a grouped layout or installing new modules. As a side effect, all attached views will also reset themselves.

Member CBibleReadWindow::saveChapter (CExportManager::Format const format)

Check if bible is nullptr!

Member CSwordModuleSearch::highlightSearchedText (QString const &content, QString const &searchedText, bool plainSearchedText)

?

Member Filters::ThmlToHtml::processText (sword::SWBuf &buf, const sword::SWKey *key, const sword::SWModule *module=nullptr) override

e.replace() instead?