-struct FD_form_tabbed_document;
-struct FD_form_doc_paper;
-struct FD_form_doc_class;
-struct FD_form_doc_language;
-struct FD_form_doc_options;
-struct FD_form_doc_bullet;
+namespace lyx {
+namespace frontend {
+
+class ControlDocument;
+class FormColorpicker;
+struct FD_document;
+struct FD_document_paper;
+struct FD_document_class;
+struct FD_document_language;
+struct FD_document_options;
+struct FD_document_bullet;
+struct FD_document_branch;