How can a button be visible if 3 of the selection field is having value = Yes.
Any reference to such code will be helpful.
The definition of the button has an attribute invisible
which is a PYSON that makes the button invisible if evaluated to True
and visible if False
. There is also the readonly
attribute which keep the button visible but prevent to click on it.
I filled Issue 9954: Document keys of ModelView._buttons - Tryton issue tracker to improve the documentation.