Thanks,
Both suggestions don’t seem to add extra space to the PDF page (I’m assuming). If the PDF page have pre-existing full body of text, adding fields or comments to the A4 space will obstruct the pre-existing text. Assumptions.
On the comments part, I’m not too sure how it works, but I will investigate, I hope the comment boxes will be a separate space outside the A4 page which can be readable together with text on the A4 page with a single middle mice button scroll down.
After testing the comments feature, it’s little yellow pop up boxes which have its usefulness or can be missed though I’m sure there a keyboard shortcut to expand all comments, though the comments box blocked part of the text on the A4 page.
I felt IMHO that adding an extra app pane for notes taking will have its usefulness in certain limited scenarios.
Respectfully, thank you for sharing.