Did you consider using a proxy style ?

@Christina123 Use mousePressEvent, it provides the cursor position as parameter https://doc.qt.io/qt-5/qwidget.html#mousePressEvent

@Staslend if your issue is solved, please don't forget to mark your post as such! Thanks.

I figured out the answer. I have to create a QSlider from scratch meaning not one created from the ui already.

So,

QSlider *slider = new MySlider(Qt::horizontal); ui->frameTestLayout->addWidget(slider); slider->setFocusPolicy(Qt::NoFocus); slider->setTickPosition(QSlider::TicksAbove); slider->setTickInterval(number);

@jsulm There're no calls to paintEvent() or update() inside updateGL()

void OpenGLWidget::updateGL() { makeCurrent(); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); //LEQUAL glEnable(GL_CULL_FACE); glFrontFace(GL_CW); glLineWidth(1.0f); // glDisable(GL_DITHER); glEnable(GL_LINE_SMOOTH); glEnable(GL_MULTISAMPLE); glViewport(0,0,m_width , m_height); m_camera = m_cameraController.toMatrix(); QVector3D lightDirection; switch (m_currView) { case TopView: lightDirection = QVector3D(0.0,0.0,1.0); break; case BottomView: lightDirection = QVector3D(0.0,0.0,-1.0); break; case LeftView: lightDirection = QVector3D(-1.0,0.0,0.0); break; case RightView: lightDirection = QVector3D(1.0,0.0,0.0); break; case FrontView: lightDirection = QVector3D(0.0,-1.0,0.0); break; case BackView: lightDirection = QVector3D(0.0,1.0,0.0); break; } lightDirection.normalize(); QVector3D directionalColor = QVector3D(0.3,0.3,0.3); QVector3D ambientLight = QVector3D(0.5,0.5,0.5); m_world.setToIdentity(); m_world.translate(m_modelBox.getCenterPoint()); m_world.rotate(m_rotation); m_world.scale(1.0f, 1.0f, m_worldZScalar); m_world.translate(-m_modelBox.getCenterPoint()); QMatrix3x3 normalMatrix = m_world.normalMatrix(); if(geometries){ if(!m_drawWireFrame){ m_programGrid->bind(); //Set MVP Uniforms m_programGrid->setUniformValue(m_projMatrixLoc, m_proj); m_programGrid->setUniformValue(m_mvMatrixLoc, m_camera * m_world); m_programGrid->setUniformValue(m_normalMatrixLoc, normalMatrix); //Set Lighting Uniforms. m_programGrid->setUniformValue(m_lightDirectionLoc, lightDirection); m_programGrid->setUniformValue(m_directionalColorLoc, directionalColor); m_programGrid->setUniformValue(m_ambientColorLoc, ambientLight); //Draw Grid Geometry geometries->drawGeometry(m_programGrid); m_programGrid->release(); //Draw Border Lines if(m_showBorders){ m_programLines->bind(); m_programLines->setUniformValue(m_projMatrixLocLines, m_proj); m_programLines->setUniformValue(m_mvMatrixLocLines, m_camera * m_world); geometries->drawLines(m_programLines, QVector3D(0.0,0.0,0.0)); m_programLines->release(); } }else{ m_programLines->bind(); m_programLines->setUniformValue(m_projMatrixLocLines, m_proj); m_programLines->setUniformValue(m_mvMatrixLocLines, m_camera * m_world); geometries->drawLines(m_programLines, QVector3D(1.0,1.0,1.0)); m_programLines->release(); } } if(wellgeometries){ glLineWidth(4.0f); m_programLines->bind(); m_programLines->setUniformValue(m_projMatrixLocLines, m_proj); m_programLines->setUniformValue(m_mvMatrixLocLines, m_camera * m_world); wellgeometries->drawLines(m_programLines, QVector3D(1.0,0.0,0.0)); m_programLines->release(); } if(m_showCompass){ glDisable(GL_DEPTH_TEST); glViewport(0,0,100,100); m_world.setToIdentity(); m_world.translate(0,0,-5); m_world.rotate(m_cameraController.rotation().inverted()); m_world.rotate(m_rotation); QMatrix4x4 proj; // Set near plane, far plane , field of view const qreal zNear = 1.0f, zFar = 150.0f, fov = 45.0; proj.setToIdentity(); proj.perspective(fov, 1.0f, zNear, zFar); m_programGrid->bind(); m_programGrid->setUniformValue(m_projMatrixLoc, proj); m_programGrid->setUniformValue(m_mvMatrixLoc, m_world); m_programGrid->setUniformValue(m_normalMatrixLoc, normalMatrix); //Set Lighting Uniforms. m_programGrid->setUniformValue(m_lightDirectionLoc, lightDirection); m_programGrid->setUniformValue(m_directionalColorLoc, directionalColor); m_programGrid->setUniformValue(m_ambientColorLoc, ambientLight); compass->drawCompassGeometry(m_programGrid); m_programGrid->release(); } //doneCurrent(); }

@alex_malyu Well, it actually not. At least in this case (I don't know if this depends on your operating system, or on the type of widget or something like that)
If I comment my update() call, paintEvent is never called, no matter how much I move the mouse over it.