Visual artifacts when style is applied to overlapping Qt PushButtons - c++

Question

In the application I'm developing, I've got sets of QPushButtons that overlay each other like so:
resize(300, 300);
QRect geometry( 100, 100 , 100 , 100 );
m_button[0] = new QPushButton( this );
m_button[0]->setGeometry( geometry );
m_button[0]->setText( "Button 1" );
m_button[1] = new QPushButton( this );
m_button[1]->setGeometry( geometry );
m_button[1]->setText( "Button 2" );
m_button[1]->raise();
Result:
But when the follows style is added at application level
QApplication app(argc, argv);
app.setStyleSheet( "QPushButton{ border-width: 1px; border-color: blue; border-style: solid;}" );
the buttons are rendered as like so:
What would be the reason for this artefact, and how can I workaround it.
Information about my application
The overlapping buttons are keys belonging to different character sets of a virtual keyboard. These keys are raised or lowered depending on the current character set.

Answer 1

You want to use a QStackedWidget and place your QPushButtons in that stack. Then you just need to raise the button you want with QStackedWidget::setCurrentIndex or QStackedWidget::setCurrentWidget.
Edit: sample code:
resize(300, 300);
QStackedWidget* stack = new QStackedWidget(this);
stack->setGeometry( 100, 100 , 100 , 100 );
m_button[0] = new QPushButton( this );
m_button[0]->setText( "Button 1 );
stack->addWidget(m_button[0]);
m_button[1] = new QPushButton( this );
m_button[1]->setText( "Button 2" );
stack->addWidget(m_button[1]);
stack->setCurrentWidget(m_button[1]); //or stack->setCurrentIndex(1);