Problem with line items count on screen

Hello Experts,

I am trying to access MB1B transaction in screen personas. material line items are varying time to time. some times I am able to access 5 line item some times I am having 8. But in sap GUI I am having 16 line items.

I have tried with various screen resolutions. I understood like the number of line items will depend on screen size.

when user 1 logged in a system he is able to access 5 line items. and when user2 logged in the same system with same screen resolution he is able to access 8 line items. sometimes we are able to access only one line item.

Is there any way to restrict this?

Thanks

Swathi