erp5_xhtml_style is required.

bt5/erp5_slideshow_style/RegisteredSkinSelectionTemplateItem/registered_skin_selection.xml

@@ -3,4 +3,8 @@
   <skin_folder>erp5_slideshow_style</skin_folder>
   <skin_selection>SlideShow</skin_selection>
  </skin_folder_selection>
+ <skin_folder_selection>
+  <skin_folder>erp5_xhtml_style</skin_folder>
+  <skin_selection>SlideShow</skin_selection>
+ </skin_folder_selection>
 </registered_skin_selection>
\ No newline at end of file

bt5/erp5_slideshow_style/bt/revision

-3
\ No newline at end of file
+4
\ No newline at end of file

bt5/erp5_slideshow_style/bt/template_registered_skin_selection_list

 erp5_slideshow_style | SlideShow
+erp5_xhtml_style | SlideShow
\ No newline at end of file