Understanding default behavior of branching?

Understanding default behavior of branching?

db 11gxe and apex 4.x
i created a master detail page , there are buttons on it by default , like
(cancel,delete,apply changes) and two buttons for getting the next order
and the previous one --there a master table for orders .
there are also branches created by default for the button getting the next
order and the button getting the previous one (the branch is conditional
ofcourse) -- the condition is when-button-clicked .
these branches are created automatically because the buttons are exist ,
and there are conditions which are "when-button-clicked" --just this
condition .
-- what i do not understand is that there are other buttons like "delete ,
cancel , apply changes" , and there were no branches created for them like
the other buttons which i mentioned above ,
although they also navigate like the other buttons , and the condition is
when-button-clicked as well ?
why in the first situation there are branches created automatically , and
in the last situation there are not ??
thanks in advance