There are a couple possibilities which come to my mind as to the
problem here;
assuming there is no bug in any of your set-ups - which could be
1 cause.
Another possibility is that you're attempting to stretch an existing
line rather than deleting the present one which you no longer desire;
if this is the case, then merely delete that which you no longer
want & replace with that which you want.
Another possibility may be whatever you mean by 'arquive' ???;
do you perchance mean archive?, as in saving the document?
if this is the case, then are you saving with a different name?,
or are you starting fresh with a blank PP?
You might try starting with a fresh/blank PP
then click on add file
then make any adjustments to the individual slides you want
then save the document with a different name;
Should be as you desire it,
Hoping this helps,