for example in Workorder Tracking Application, when user moves to PLAN tab, record should save.
Export presentation XML file from application designer,
filter workorder tracking application,
note: make a copy (backup)
open XML in notepad
find 'tab' element i.e. <tab id="plans"
add tabchangeevent="save" property in tab element
it will look after adding
<tab id="plans" label="Plans" tabchangeevent="save">