How to add a tick mark to a slider if it cannot inherit QSlider

Question

I have a Qt dialog and there is a slider in it, when the dialog is initialized the slider will be set a value. In order to remind the user what is the default value, I want

Answer 1

Easiest way I can think off is:

Add QSlider to QSlider (like you do it with layouts and QFrames). Slider above will be your current slider (clickable one). Slider below will be your "default tick position" value.

#include 
#include 
#include 

int main(int argc, char * argv[])
{
    QApplication app(argc, argv);

    QSlider * defaultValueSlider = new QSlider();
    QSlider * valueSlider = new QSlider(defaultValueSlider);
    QVBoxLayout * lay = new QVBoxLayout(defaultValueSlider);
    lay->setContentsMargins(0, 0, 0, 0);
    lay->setSpacing(0);
    lay->addWidget(valueSlider);
    defaultValueSlider->setRange(0, 100);
    valueSlider->setRange(0, 100);
    defaultValueSlider->setValue(30);

    defaultValueSlider->show();

    return app.exec();
}