diff --git a/src/propgrid/propgridiface.cpp b/src/propgrid/propgridiface.cpp
index 6085f50a22..ea19305d7f 100644
--- a/src/propgrid/propgridiface.cpp
+++ b/src/propgrid/propgridiface.cpp
@@ -284,8 +284,10 @@ void wxPropertyGridInterface::SetPropertyReadOnly( wxPGPropArg id, bool set, int
     }
     else
     {
-        // Do nothing if flag is already set.
-        if ( p->HasFlag(wxPG_PROP_READONLY) )
+        // Do nothing if flag is already set as required.
+        if ( set && p->HasFlag(wxPG_PROP_READONLY) )
+            return;
+        if ( !set && !p->HasFlag(wxPG_PROP_READONLY) )
             return;
 
         p->ChangeFlag(wxPG_PROP_READONLY, set);