pressing enter without input results in player search failure

src/Mtlstats/Prompt.hs

@@ -168,7 +168,9 @@ selectPlayerPrompt pStr callback = Prompt
       sel
     C.moveCursor row col
   , promptCharCheck = const True
-  , promptAction = \sStr -> do
+  , promptAction = \sStr -> if null sStr
+    then callback Nothing
+    else do
       players <- gets $ view $ database.dbPlayers
       case playerSearchExact sStr players of
         Just (n, _) -> callback $ Just n