diff -r 41300fa6a67c -r f7bc934e204c src/gui/itemviews/qstyleditemdelegate.cpp
--- a/src/gui/itemviews/qstyleditemdelegate.cpp	Tue Feb 02 00:43:10 2010 +0200
+++ b/src/gui/itemviews/qstyleditemdelegate.cpp	Wed Mar 31 11:06:36 2010 +0300
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
@@ -747,13 +747,8 @@
         return false;
     }
 
-    Qt::CheckState state;
-    if ( flags & Qt::ItemIsTristate ) {
-        state = static_cast<Qt::CheckState>( (value.toInt() + 1) % 3 );
-    } else {
-        state = (static_cast<Qt::CheckState>(value.toInt()) == Qt::Checked
+    Qt::CheckState state = (static_cast<Qt::CheckState>(value.toInt()) == Qt::Checked
                             ? Qt::Unchecked : Qt::Checked);
-    }
     return model->setData(index, state, Qt::CheckStateRole);
 }