It was initialized in header

src/libkdepim/progresswidget/progressdialog.cpp

@@ -218,7 +218,6 @@ void TransactionItemView::slotLayoutFirstItem()
 
 TransactionItem::TransactionItem(QWidget *parent, ProgressItem *item, bool first)
     : QWidget(parent)
-    , mCancelButton(nullptr)
     , mItem(item)
 {
     QVBoxLayout *vboxLayout = new QVBoxLayout(this);