That sounds odd. You clicked the arrows & that didn't change things? There's also drag points which allow you to drag each windows size. Normally there's one dot (vertical drag) in between the search results & download window. There's another (horizontal drag) between the search function itself & the other results & downlds panes.

If you can't work it out then, go to your LW Preferences & make a note of all your settings. Then close LW. Now go /Users/your_username/Library/Preferences/LimeWire & locate your LW Preferences folder. Trash it. Then re-open LW. Then reset your LW prefs settings.