diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 18c06c0da4..ccb4f06eb4 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -114,7 +114,17 @@ static const int SIZER_FLAGS_MASK =
 
 #endif // wxDEBUG_LEVEL
 
-#define ASSERT_VALID_SIZER_FLAGS(f)  wxASSERT_VALID_FLAGS(f, SIZER_FLAGS_MASK)
+#define ASSERT_INCOMPATIBLE_NOT_USED_IMPL(f, f1, n1, f2, n2) \
+    wxASSERT_MSG(((f) & (f1 | f2)) != (f1 | f2), \
+                 n1 " and " n2 " can't be used together")
+
+#define ASSERT_INCOMPATIBLE_NOT_USED(f, f1, f2) \
+    ASSERT_INCOMPATIBLE_NOT_USED_IMPL(f, f1, #f1, f2, #f2)
+
+#define ASSERT_VALID_SIZER_FLAGS(f) \
+    wxASSERT_VALID_FLAGS(f, SIZER_FLAGS_MASK); \
+    ASSERT_INCOMPATIBLE_NOT_USED(f, wxALIGN_CENTRE_HORIZONTAL, wxALIGN_RIGHT); \
+    ASSERT_INCOMPATIBLE_NOT_USED(f, wxALIGN_CENTRE_VERTICAL, wxALIGN_BOTTOM)
 
 
 void wxSizerItem::Init(const wxSizerFlags& flags)
diff --git a/tests/sizers/boxsizer.cpp b/tests/sizers/boxsizer.cpp
index c8f59273ac..75534d2c96 100644
--- a/tests/sizers/boxsizer.cpp
+++ b/tests/sizers/boxsizer.cpp
@@ -44,6 +44,7 @@ private:
         CPPUNIT_TEST( BestSizeRespectsMaxSize );
         CPPUNIT_TEST( RecalcSizesRespectsMaxSize1 );
         CPPUNIT_TEST( RecalcSizesRespectsMaxSize2 );
+        CPPUNIT_TEST( IncompatibleFlags );
     CPPUNIT_TEST_SUITE_END();
 
     void Size1();
@@ -52,6 +53,7 @@ private:
     void BestSizeRespectsMaxSize();
     void RecalcSizesRespectsMaxSize1();
     void RecalcSizesRespectsMaxSize2();
+    void IncompatibleFlags();
 
     wxWindow *m_win;
     wxSizer *m_sizer;
@@ -376,3 +378,10 @@ void BoxSizerTestCase::RecalcSizesRespectsMaxSize2()
     CPPUNIT_ASSERT_EQUAL(50, child2->GetSize().GetHeight());
     CPPUNIT_ASSERT_EQUAL(125, child3->GetSize().GetHeight());
 }
+
+void BoxSizerTestCase::IncompatibleFlags()
+{
+    WX_ASSERT_FAILS_WITH_ASSERT(
+        m_sizer->Add(10, 10, 0, wxALIGN_BOTTOM | wxALIGN_CENTRE_VERTICAL)
+    );
+}