When create new record in detail tab, focus move to parent tab and that cause to use mouse to bring focus back to detail tab.
For supporting quick entry, user focus should stay in detail tab while user to alt+a.
Step to reproduce:
Enter SO header
Now click on new button on order line in detail tab layout
Focus will move to header tab
go and change focus to order line tab, create entry and then do alt+a
Again focus move to header tab