diff --git a/qt/qt_common/map_widget.cpp b/qt/qt_common/map_widget.cpp
index 0395988cff..7d7ab8f432 100644
--- a/qt/qt_common/map_widget.cpp
+++ b/qt/qt_common/map_widget.cpp
@@ -268,8 +268,10 @@ void MapWidget::Build()
                            QVector4D(1.0, -1.0, 1.0, 0.0)};
   m_vbo->allocate(static_cast<void*>(vertices), sizeof(vertices));
   QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
+  // 0-index of the buffer is linked to "a_position" attribute in vertex shader.
+  // Introduced in https://github.com/organicmaps/organicmaps/pull/9814
   f->glEnableVertexAttribArray(0);
-  f->glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), nullptr);
+  f->glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(QVector4D), nullptr);
   m_vbo->release();
 
   m_program->release();