[KevinH]

According to MS docs, this automatic adding of recently opened things is a "feature" of using any of the following Windows API calls:

SHAddToRecentDocs
GetOpenFileName
IFileOpenDialog

And of course in Qt QDialog's Native getOpenFilename on Windows there is a call to:

class QWindowsNativeOpenFileDialog : public QWindowsNativeFileDialogBase
{
public:
    explicit QWindowsNativeOpenFileDialog(const QWindowsFileDialogSharedData &data) :
        QWindowsNativeFileDialogBase(data) {}
    QList<QUrl> selectedFiles() const override;
    QList<QUrl> dialogResult() const override;

private:
    inline IFileOpenDialog *openFileDialog() const
        { return static_cast<IFileOpenDialog *>(fileDialog()); }
};

So we would need to change the to use non-native file dialogs in Qt anyplace we did not want Windows to add to the list such as Plugin Loading or AddExisting... or ...

This "feature" seems to have no way to disable it on a program specific level.

A horrible design decision on Windows part.