Fix tool buttons in details widget on Mac with raster engine.

Task-number: QTBUG-15170

src/libs/utils/detailsbutton.cpp

@@ -54,6 +54,11 @@ FadingPanel::FadingPanel(QWidget *parent) :
 	setPalette(pal);
 }
 
+void FadingPanel::setOpacity(qreal value)
+{
+	m_opacityEffect->setOpacity(value);
+}
+
 void FadingPanel::fadeTo(float value)
 {
 	QPropertyAnimation *animation = new QPropertyAnimation(m_opacityEffect, "opacity");

src/libs/utils/detailsbutton.h

@@ -43,6 +43,7 @@ class QTCREATOR_UTILS_EXPORT FadingPanel : public QWidget
 {
 public:
 	FadingPanel(QWidget *parent = 0);
+	void setOpacity(qreal value);
 	void fadeTo(float value);
 protected:
 	QGraphicsOpacityEffect *m_opacityEffect;

src/libs/utils/detailswidget.cpp

@@ -224,6 +224,9 @@ namespace Utils {
         d->m_toolWidget->adjustSize();
         d->m_grid->addWidget(d->m_toolWidget, 0, 1, 1, 1, Qt::AlignRight);
 
+#ifdef Q_WS_MAC
+        d->m_toolWidget->setOpacity(1.0);
+#endif
         changeHoverState(d->m_hovered);
     }