Windows/Qt 4: after call showMinimized() on translucent/frameless window and manually restoring it, window is no longer responsive

DropShadowWidget::DropShadowWidget(QWidget *parent)
: QDialog(parent)

{ setWindowFlags(Qt::FramelessWindowHint | Qt::Dialog); setAttribute(Qt::WA_TranslucentBackground); connect(this, SIGNAL(showMin()), this, SLOT(showMinimized())); connect(my_button, SIGNAL(clicked()), this, SIGNAL(showMin())); }

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We can minimize the window correctly by click my_button, then restore the window by hand for normal state, then we cannot click any button (I use QToolbutton)!

The same code works well in QT5, but has the problem in QT4.86. So I am sure that it is the problem of QT4, not the problem of my code. Please resolve this problem in the next version 4
87 (maybe you should simplely replace some codes by QT5)
Env: WIN7 x64, VC2008 SP1, QT4.86 (compile in MinGW has the same problem)