Created attachment 173176 [details]
Example file from PowerPoint

Attached PP-made file demonstrates some slide show settings that have no equivalent setting in Impress.
When saved in Impress, these values are lost. It would be nice to roundtrip them via interopgrabbags.

Steps to reproduce:
    1. Open attached file in Impress
    2. Save it as PPTX, reopen it in PowerPoint
    3. Compare the Slide Show settings in PowerPoint

Actual results:
Show Media Controls box on the Ribbon is checked.
No Narrations box in dialog is unchecked.
Ink color is default red. (Note: while this can be changed in Impress, it’s not saved in ODP / as global setting either)
Laser pointer color is default red.

Expected results:
Show Media Controls box on the Ribbon is kept unchecked.
No Narrations box in dialog is checked.
Ink color is kept orange.
Laser pointer color is kept green.

LibreOffice details:
Version: 7.3.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: 2a7e64da7f385de8dbba1802530e251cf29259fb
CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: default; VCL: win
Locale: en-US (hu_HU); UI: en-US
Calc: CL