About this issue above, sometimes it happens to me. I don't know the exact steps to reproduce it, but it oftens happen when I save a book and close the Editor with the search pannel opened. Then, the next time I open the Editor again, the central pannel takes most of the screen, narrowing the side docks.
I've seen this mentioned before
here on the forum, and what was said is that the search pannel requires a minimal width when it is launched, so if the central pannel is narrower than that minimal value, it will stretch, destorting your setup.
Is this correct, @Kovid?