Clicking on Cancel in the FileChooser popup window of a Binary widget result in an error
Here's the Traceback:
ERROR:tryton.common.common: File "/home/nicoe/projets/tryton/tryton-env/TextInBinary/tryton/tryton/gui/window/view_form/view/form_gtk/binary.py", line 92, in select
'file:///' + file_selection(
TypeError: can only concatenate str (not "NoneType") to str