LibreOffice 5 Impress impedes customization of paper size and customization

I am using Libre Office 5 Impress. This is the fresh install from upgrading from Ubuntu 14.04 to 16.04. The package info are

Build ID: 1:5.1.4-0ubuntu1
CPU Threads: 4; OS Version: Linux 4.4; UI Render: default;
Locale: en-US (en_US.UTF-8)

I want to print the handouts on A4 paper in portrait arrangement.

However the Print dialogue box (From the File > Print > Properties) holds different standards (Letter, landscape) and it does not allow me to customize these (the boxes are greyed out).

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The settings that I wish are correctly in place in the printer’s own properties. Previously, before the Ubuntu upgrade and LibreOffice update, this was understood by LibreOffice. In other words, this current version of LibreOffice appears to force such own internal standards and prevent the user to customize them.

How do I get back the permission to change paper size and orientation?

I had created the same post on the SuperUser forum. I will take care of cross linking the answers. Please do not hesitate to post your answer here (and there too, if you like)

Agreed. Waste of time, paper, ink and mess in printer. Where does LO get the settings from - not in my CUPS or template or printer or slide properties.

Workaround is to export to a PDF and print that.