diff --git a/interface/wx/propgrid/propgrid.h b/interface/wx/propgrid/propgrid.h
index 3993ada9b2..6e6052d235 100644
--- a/interface/wx/propgrid/propgrid.h
+++ b/interface/wx/propgrid/propgrid.h
@@ -926,6 +926,8 @@ public:
 
     /**
         Redraws given property.
+
+        @param p Valid, i.e. non-@NULL, property pointer.
     */
     virtual void RefreshProperty( wxPGProperty* p );
 
@@ -1143,6 +1145,8 @@ public:
     /**
         Draws item, children, and consecutive parents as long as category is
         not met.
+
+        @param p Valid, i.e. non-@NULL, property pointer.
      */
     void DrawItemAndValueRelated( wxPGProperty* p );
 
diff --git a/src/propgrid/propgrid.cpp b/src/propgrid/propgrid.cpp
index b92a6c0bef..a1ed7af8be 100644
--- a/src/propgrid/propgrid.cpp
+++ b/src/propgrid/propgrid.cpp
@@ -1378,7 +1378,8 @@ void wxPropertyGrid::OnDPIChanged(wxDPIChangedEvent &event)
     CalculateFontAndBitmapStuff(m_vspacing);
     Refresh();
 
-    RefreshProperty(GetSelection());
+    if ( wxPGProperty* const selected = GetSelection() )
+        RefreshProperty(selected);
 
     event.Skip();
 }
@@ -2567,6 +2568,8 @@ void wxPropertyGrid::DrawItems( const wxPGProperty* p1, const wxPGProperty* p2 )
 
 void wxPropertyGrid::RefreshProperty( wxPGProperty* p )
 {
+    wxCHECK_RET( p, wxS("invalid property id") );
+
     if ( m_pState->DoIsPropertySelected(p) || p->IsChildSelected(true) )
     {
         // NB: We must copy the selection.
@@ -2585,6 +2588,8 @@ void wxPropertyGrid::RefreshProperty( wxPGProperty* p )
 
 void wxPropertyGrid::DrawItemAndValueRelated( wxPGProperty* p )
 {
+    wxCHECK_RET( p, wxS("invalid property id") );
+
     if ( IsFrozen() )
         return;