diff --git a/include/wx/bmpbndl.h b/include/wx/bmpbndl.h
index e55ba08f44..6657fb8056 100644
--- a/include/wx/bmpbndl.h
+++ b/include/wx/bmpbndl.h
@@ -100,7 +100,7 @@ public:
     // Get preferred size, i.e. usually the closest size in which a bitmap is
     // available to the ideal size determined from the default size and the DPI
     // scaling, for the given window.
-    wxSize GetPreferredSizeFor(wxWindow* window) const;
+    wxSize GetPreferredSizeFor(const wxWindow* window) const;
     wxSize GetPreferredSizeAtScale(double scale) const;
 
     // Get bitmap of the specified size, creating a new bitmap from the closest
diff --git a/interface/wx/bmpbndl.h b/interface/wx/bmpbndl.h
index c9392657fa..5e8b111358 100644
--- a/interface/wx/bmpbndl.h
+++ b/interface/wx/bmpbndl.h
@@ -275,7 +275,7 @@ public:
 
         @param window Non-null and fully created window.
      */
-    wxSize GetPreferredSizeFor(wxWindow* window) const;
+    wxSize GetPreferredSizeFor(const wxWindow* window) const;
 
     /**
         Get bitmap of the specified size, creating a new bitmap from the closest
diff --git a/src/common/bmpbndl.cpp b/src/common/bmpbndl.cpp
index af6702d08a..202c1fc435 100644
--- a/src/common/bmpbndl.cpp
+++ b/src/common/bmpbndl.cpp
@@ -375,7 +375,7 @@ wxSize wxBitmapBundle::GetDefaultSize() const
     return m_impl->GetDefaultSize();
 }
 
-wxSize wxBitmapBundle::GetPreferredSizeFor(wxWindow* window) const
+wxSize wxBitmapBundle::GetPreferredSizeFor(const wxWindow* window) const
 {
     wxCHECK_MSG( window, wxDefaultSize, "window must be valid" );