LOL. Old eyes. What can I say. Glad you brought that up.
The problem IS font size related. If I close all files, open a new file and reduce the font size, AND close the new file, THEN open a new file and open search and replace, the whole search and replace is visible.
However, if I have ANY font size, open Search and Replace and then increase the font-size, the Search and Replace area doesn't grow with the increase in font-size.
So, it seems the height of the Search and Replace bar is fixed. I don't know whether others would consider this a bug or not. I would think the Search and Replace should grow with the fonts, but I would understand if others think differently.