Fix wxGTK wxBitmapComboBox::SetValue() not working if wxCB_READONLY window style was used

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59686 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/bmpcbox.cpp

@@ -288,6 +288,8 @@ void wxBitmapComboBox::WriteText(const wxString& value)
 {
     if ( GetEntry() )
         wxComboBox::WriteText(value);
+    else
+        SetStringSelection(value);
 }
 
 wxString wxBitmapComboBox::GetValue() const