That's for either of 2 reasons I can think of: 1. Autocomplete, which fills in the text for a previous search that has the same 1st 2-3 letters. You can trurn this off by going to LW's menu Options-View & Autocomplete & unticking the option box. (or LW Prefs-View-Autocomplete for OSX)
(Click link to see example image)
2. You may need to resize the partitions on your LW interface. You can drag the bottom right corner, or/& drag any of the small arrows that separate each of the sections on the main window.
(Click link to see example image)