My paint() is not working for all items in scene - c++

Question

I have a QGraphicsScene which contains some symbols (many symbols are repeated) . These symbols consist of line. I have created a separate class for line which inherits from QGraphicsLineItem. All these lines are grouped under one entity using QGraphicsItemGroup.
Here is code structure:
I have a map which contains all the line co-ordinates. I am taking co-ordinates from map and giving those to Qt's API.
myGroup.h
class myGroup: public QGraphicsItemGroup
{
virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
void PaintSymbol(QGraphicsItem *item, QPainter *painter, const
QStyleOptionGraphicsItem *option);
}
myGroup.cpp
void myGroup::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
{
auto copied_option = *option;
copied_option.state &= ~QStyle::State_Selected;
auto selected = option->state & QStyle::State_Selected;
myGroup::paint(painter, &copied_option, widget);
if (selected)
{
foreach (QGraphicsItem* item, _scene->selectedItems()) {
myGroup* inst = qgraphicsitem_cast<myGroup*>(item);
if (!inst)
continue;
QList<QGraphicsItem*> childItems = inst->childItems();
foreach (QGraphicsItem* chItem, childItems) {
if (myLine* line = dynamic_cast<myLine*>(chItem)) {
PaintSymbol(line, painter, option);
}
void myGroup::PaintSymbol(QGraphicsItem* item, QPainter* painter, const
QStyleOptionGraphicsItem* option)
{
painter->save();
painter->setPen(QPen(option->palette.windowText(), 0, Qt::SolidLine));
if(myLine* line = dynamic_cast<myLine*>(item))
painter->drawPath(line->shape());
painter->restore();
}
myLine.h
class myLine: public QGraphicsLineItem {
public:
myLine();
myLine(int x1, int y1, int x2, int y2, QGraphicsItem *parent = nullptr);
};
DrawFun().cpp
myGroup* GroupItem= new myGroup();
for( iterating over map )
{
// taking co-ordinates
myLine* line = new myLine(first, second, third, fourth);
GroupItem->addToGroup(line);
}
// Control comes here when I click on symbol on screen.
HighlightObject()
{
// here I find symbols under click. ( i.e. itemUnderClick )
myGroup* gItem = qgraphicsitem_cast<myGroup*>(itemUnderClick);
if (gItem)
gItem->setSelected(true); // from here control goes to paint() in myGroup
}
Now issue is :
For some symbols, selected variable in paint() gives value as ( in debugging I found)
QStyle::State_None (0x0000)
And for some symbols it gives value as :
QStyle::State_Selected (0x8000)
For value : QStyle::State_None (0x0000) paint() does not highlight object.
Where am I wrong in heighlighting all objects ?