diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 31f2503850..badc6724ab 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -2300,7 +2300,12 @@ wxSize wxBoxSizer::CalcMin()
     m_totalProportion = 0;
     m_minSize = wxSize(0, 0);
 
-    // calculate the minimal sizes for all items and count sum of proportions
+    // The minimal size for the sizer should be big enough to allocate its
+    // element at least its minimal size but also, and this is the non trivial
+    // part, to respect the children proportion. To satisfy the latter
+    // condition we must find the greatest min-size-to-proportion ratio for all
+    // elements with non-zero proportion.
+    float maxMinSizeToProp = 0.;
     for ( wxSizerItemList::const_iterator i = m_children.begin();
           i != m_children.end();
           ++i )
@@ -2311,13 +2316,31 @@ wxSize wxBoxSizer::CalcMin()
             continue;
 
         const wxSize sizeMinThis = item->CalcMin();
-        SizeInMajorDir(m_minSize) += GetSizeInMajorDir(sizeMinThis);
+        if ( const int propThis = item->GetProportion() )
+        {
+            float minSizeToProp = GetSizeInMajorDir(sizeMinThis);
+            minSizeToProp /= propThis;
+
+            if ( minSizeToProp > maxMinSizeToProp )
+                maxMinSizeToProp = minSizeToProp;
+
+            m_totalProportion += item->GetProportion();
+        }
+        else // fixed size item
+        {
+            // Just account for its size directly
+            SizeInMajorDir(m_minSize) += GetSizeInMajorDir(sizeMinThis);
+        }
+
+        // In the transversal direction we just need to find the maximum.
         if ( GetSizeInMinorDir(sizeMinThis) > GetSizeInMinorDir(m_minSize) )
             SizeInMinorDir(m_minSize) = GetSizeInMinorDir(sizeMinThis);
-
-        m_totalProportion += item->GetProportion();
     }
 
+    // Using the max ratio ensures that the min size is big enough for all
+    // items to have their min size and satisfy the proportions among them.
+    SizeInMajorDir(m_minSize) += maxMinSizeToProp*m_totalProportion;
+
     return m_minSize;
 }
 
diff --git a/tests/sizers/boxsizer.cpp b/tests/sizers/boxsizer.cpp
index 558f15883b..ca203d2379 100644
--- a/tests/sizers/boxsizer.cpp
+++ b/tests/sizers/boxsizer.cpp
@@ -43,10 +43,12 @@ private:
     CPPUNIT_TEST_SUITE( BoxSizerTestCase );
         CPPUNIT_TEST( Size1 );
         CPPUNIT_TEST( Size3 );
+        CPPUNIT_TEST( CalcMin );
     CPPUNIT_TEST_SUITE_END();
 
     void Size1();
     void Size3();
+    void CalcMin();
 
     wxWindow *m_win;
     wxSizer *m_sizer;
@@ -248,3 +250,54 @@ void BoxSizerTestCase::Size3()
         }
     }
 }
+
+void BoxSizerTestCase::CalcMin()
+{
+    static const unsigned NUM_TEST_ITEM = 3;
+
+    static const struct CalcMinTestData
+    {
+        // proportions of the elements, if one of them is -1 it means to not
+        // use this window at all in this test
+        int prop[NUM_TEST_ITEM];
+
+        // minimal sizes of the elements in the sizer direction
+        int minsize[NUM_TEST_ITEM];
+
+        // the expected minimal sizer size
+        int total;
+    } calcMinTestData[] =
+    {
+        { {  1,  1, -1 }, {  30,  50,   0 },  100 },
+        { {  1,  1,  0 }, {  30,  50,  20 },  120 },
+        { { 10, 10, -1 }, {  30,  50,   0 },  100 },
+        { {  1,  2,  2 }, {  50,  50,  80 },  250 },
+        { {  1,  2,  2 }, { 100,  50,  80 },  500 },
+    };
+
+    unsigned n;
+    wxWindow *child[NUM_TEST_ITEM];
+    for ( n = 0; n < NUM_TEST_ITEM; n++ )
+        child[n] = new wxWindow(m_win, wxID_ANY);
+
+    for ( unsigned i = 0; i < WXSIZEOF(calcMinTestData); i++ )
+    {
+        m_sizer->Clear();
+
+        const CalcMinTestData& cmtd = calcMinTestData[i];
+        for ( n = 0; n < NUM_TEST_ITEM; n++ )
+        {
+            if ( cmtd.prop[n] != -1 )
+            {
+                child[n]->SetInitialSize(wxSize(cmtd.minsize[n], -1));
+                m_sizer->Add(child[n], wxSizerFlags(cmtd.prop[n]));
+            }
+        }
+
+        WX_ASSERT_EQUAL_MESSAGE
+        (
+            ("In test #%u", i),
+            cmtd.total, m_sizer->CalcMin().x
+        );
+    }
+}