Libreoffice 5.1.3 Ubuntu extension icon not displayed

When I launch the extension I am developing from eclipse I have the following warning message.
(soffice:5960): Gdk-WARNING **: gdk_window_set_icon_list: icons too large

The program (the lbreoffice extension) run but no icon or menu bar are displayed inside calc.
It works fine in Windows 10, so I wonder how to fix it on Ubuntu (16.04 64bits)

Thank you for your help.