When showing Caption/info in a PDF, the viewing window containing the PDF moves down by the same distance taken up by the text displayed at the bottom. Ideally, it shouldn't move down; instead, it should move up to allow the text to be read, without overlaying the image.
This is exactly how it works with images, and PDF files should do the same, with a scroll bar appearing for extra-long descriptions.
I have tested this using Windows 11 with Chrome and MS Edge, and on an Android Tablet and the results are all the same.
Of course, the effect is worse if the PDF has a long description!
Attached is a screenshot of the problem.
See link to my Album:
Opening of Homesford Water Treatment Works