In ME23N, No Pop up in Pdf Preview

Hi Team,

I require help in following case, in ME23N there is option of Print Preview.

In that, there is option of Pdf Preview. Initially we were getting Pop up to Open, Save & Cancel option

Below that there was Check Box to select Always Ask before opening the file or something similar.

I unticked it, so I dont get any pop up.

Now, I want to have option of Pop Up but no idea where it can be done.

Help required in this case.

Regards

Nitin Desai