If you cannot drag the bottom or side of the window or the bottom corner outward, then close LW. Delete the LW main preferences folder: Deleting LW Preferences folder in OSX

Remove the downloads.dat file before you delete the preferences folder! After you open LW, you will be asked about set up questions again. After answering those questions, go to the preferences options ⌘ , & see if the problem is fixed with the window. After you close LW, return the downloads.dat file back into the new preferences folder replacing any newer one. This must only be done whilst LW is closed.

If this does not help, post back and tell us.