In recent versions, the Find Panel opens with ctrl-f but I always need to grab it and stretch it up or use the scrollbar so that I can click the FIND button (and I know I could just hit enter).
You can resize it to however large you want.
Settings > Set Lister Defaults (or Set As Default Lister, if using older toolbars/menus) if it doesn't automatically save the new size.
(If it still doesn't save the same after doing that, and you're opening it via a Layout, or Style, then you need to update those similarly.)