diff -r 56cd8111b7f7 -r 41300fa6a67c src/gui/styles/qstylehelper.cpp
--- a/src/gui/styles/qstylehelper.cpp	Tue Jan 26 12:42:25 2010 +0200
+++ b/src/gui/styles/qstylehelper.cpp	Tue Feb 02 00:43:10 2010 +0200
@@ -154,7 +154,7 @@
         }
 
         qreal m = -(y2 - y1) / (x2 - x1);
-        _angle = atan(m) *  rad_factor;
+        _angle = qAtan(m) *  rad_factor;
 
         if (p1.x() < p2.x())
             _angle = 180 - _angle;