I found out the hard way:
If you go to your appstacks and use the default "Show 10" drop down, and then click the select all check box/radio button....it will select only 10 items.
But, if through the course of your day, you decide to "Show 100" and then even later revert that to "Show 10"....hitting the select all check box will select 100 items.
Be careful out there.
