diff --git a/lib/TerminalDisplay.cpp b/lib/TerminalDisplay.cpp
index 8299c44..cd1b2ea 100644
--- a/lib/TerminalDisplay.cpp
+++ b/lib/TerminalDisplay.cpp
@@ -234,6 +234,8 @@ void TerminalDisplay::setVTFont(const QFont& f)
 
 #ifdef Q_WS_MAC
 #if QT_VERSION >= 0x040700
+    // mac uses floats for font width specification.
+    // this ensures the same handling for all platforms
     font.setStyleStrategy(QFont::ForceIntegerMetrics);
 #else
 #warning "Correct handling of the QFont metrics requited Qt>=4.7"
@@ -557,14 +559,14 @@ void TerminalDisplay::setOpacity(qreal opacity)
 
     // enable automatic background filling to prevent the display
     // flickering if there is no transparency
-    /*if ( color.alpha() == 255 )
+    if ( color.alpha() == 255 )
     {
         setAutoFillBackground(true);
     }
     else
     {
         setAutoFillBackground(false);
-    }*/
+    }
 
     _blendColor = color.rgba();
 }
diff --git a/lib/qtermwidget.cpp b/lib/qtermwidget.cpp
index 8220fb8..dc329a7 100644
--- a/lib/qtermwidget.cpp
+++ b/lib/qtermwidget.cpp
@@ -196,6 +196,13 @@ void QTermWidget::setTerminalFont(QFont &font)
     m_impl->m_terminalDisplay->setVTFont(font);
 }
 
+void QTermWidget::setTerminalOpacity(qreal level)
+{
+    if (!m_impl->m_terminalDisplay)
+        return;
+    m_impl->m_terminalDisplay->setOpacity(level);
+}
+
 void QTermWidget::setShellProgram(const QString &progname)
 {
     if (!m_impl->m_session)
diff --git a/lib/qtermwidget.h b/lib/qtermwidget.h
index b24ba41..f389e6a 100644
--- a/lib/qtermwidget.h
+++ b/lib/qtermwidget.h
@@ -66,6 +66,8 @@ public:
     // otherwise symbols' position could be incorrect
     void setTerminalFont(QFont & font);
 
+    void setTerminalOpacity(qreal level);
+
     //environment
     void setEnvironment(const QStringList & environment);