When you edit the document library block, the window opens but you can only see the top slither!
Very frustrating as every time you have to drag the bottom of the window to expand it enough to see the settings. Im sure this is a simple code edit in the core.
There was something like this reported as an issue on GitHub. I can’t remember the details. You may need to go back a while to find the issue. It may not have been the doc library. May have been about another block with a similar bug.
I saw it on a client site, but it seemed to be sporadic. It’s been a while, but I feel like it may have stopped doing it at some point, although that doesn’t make any sense…
I do know of a workaround, at least for adding the block. Rather than drag the block from the sidebar to the area, click on the area tab and select Add Block. Then click on the Document Library block in the sidebar.
For some reason, adding it this way gives you a more normal-height modal window: