diff --git a/src/common/graphcmn.cpp b/src/common/graphcmn.cpp
index 8c74fa3727..0d3d777601 100644
--- a/src/common/graphcmn.cpp
+++ b/src/common/graphcmn.cpp
@@ -436,6 +436,9 @@ void wxGraphicsPathData::AddRoundedRectangle( wxDouble x, wxDouble y, wxDouble w
         AddRectangle(x,y,w,h);
     else
     {
+        wxDouble maxR = std::min(w, h) / 2.0;
+        if ( radius > maxR ) radius = maxR;
+
         MoveToPoint(x+w, y+h/2);
         AddArc(x+w-radius, y+h-radius, radius, 0.0, M_PI/2.0, true);
         AddArc(x+radius, y+h-radius, radius, M_PI/2.0, M_PI, true);
diff --git a/src/gtk/dcclient.cpp b/src/gtk/dcclient.cpp
index f02997977d..d0ff97cd49 100644
--- a/src/gtk/dcclient.cpp
+++ b/src/gtk/dcclient.cpp
@@ -864,6 +864,9 @@ void wxWindowDCImpl::DoDrawRoundedRectangle( wxCoord x, wxCoord y, wxCoord width
 
     if (radius < 0.0) radius = - radius * ((width < height) ? width : height);
 
+    wxDouble maxR = std::min(width, height) / 2.0;
+    if ( radius > maxR ) radius = maxR;
+
     wxCoord xx = XLOG2DEV(x);
     wxCoord yy = YLOG2DEV(y);
     wxCoord ww = m_signX * XLOG2DEVREL(width);