diff -r 2f34d5167611 -r fcece45ef507 src/gui/itemviews/qitemdelegate.cpp
--- a/src/gui/itemviews/qitemdelegate.cpp	Fri Apr 16 15:50:13 2010 +0300
+++ b/src/gui/itemviews/qitemdelegate.cpp	Mon May 03 13:17:34 2010 +0300
@@ -1297,14 +1297,8 @@
         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);
 }