Fix XMonad.Prompt wraparound when maxComplRows not Nothing xmonad#217

CHANGES.md

@@ -35,6 +35,10 @@
     Added `sorter` to `XPConfig` used to sort the possible completions by how
     well they match the search string (example: `XMonad.Prompt.FuzzyMatch`).
 
+    Fixes [issue #217](https://github.com/xmonad/xmonad-contrib/issues/217), where
+    using tab to wrap around the completion rows would fail when maxComplRows is
+    restricting the number of rows of output.
+
 ## 0.15
 
 ### Breaking Changes

XMonad/Prompt.hs

@@ -851,8 +851,8 @@ bufferOne xs x = (null xs && null x,True)
 nextComplIndex :: XPState -> Int -> (Int,Int)
 nextComplIndex st nitems = case complWinDim st of
   Nothing -> (0,0) --no window dims (just destroyed or not created)
-  Just (_,_,_,_,_,yy) -> let
-    (ncols,nrows) = (nitems `div` length yy + if (nitems `mod` length yy > 0) then 1 else 0, length yy)
+  Just (_,_,_,_,xx,yy) -> let
+    (ncols,nrows) = (length xx, length yy)
     (currentcol,currentrow) = complIndex st
     in if (currentcol + 1 >= ncols) then --hlight is in the last column
          if (currentrow + 1 < nrows ) then --hlight is still not at the last row