diff --git a/src/wxmac/src/mac/wx_gbox.cc b/src/wxmac/src/mac/wx_gbox.cc
index 949c273060..87d8692f25 100644
--- a/src/wxmac/src/mac/wx_gbox.cc
+++ b/src/wxmac/src/mac/wx_gbox.cc
@@ -154,7 +154,10 @@ void wxGroupBox::Refresh(void)
 
 void wxGroupBox::SetPhantomSize(int w, int h)
 {
-  phantom_height = h;
+  if (phantom_height != h) {
+    phantom_height = h;
+    OnClientAreaDSize(0, 1, 0, 0);
+  }
 }
 
 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
diff --git a/src/wxmac/src/mac/wx_tabc.cc b/src/wxmac/src/mac/wx_tabc.cc
index 498b99237e..41505f9732 100644
--- a/src/wxmac/src/mac/wx_tabc.cc
+++ b/src/wxmac/src/mac/wx_tabc.cc
@@ -229,7 +229,10 @@ void wxTabChoice::Refresh(void)
 
 void wxTabChoice::SetPhantomSize(int w, int h)
 {
-  phantom_height = h;
+  if (phantom_height != h) {
+    phantom_height = h;
+    OnClientAreaDSize(0, 1, 0, 0);
+  }
 }
 
 extern Bool wx_propagate_key;