diff --git a/Bustle/Diagram.hs b/Bustle/Diagram.hs
index d558beb..ef96d60 100644
--- a/Bustle/Diagram.hs
+++ b/Bustle/Diagram.hs
@@ -450,7 +450,7 @@ mkLayout :: (MonadIO m)
 mkLayout s e a = liftIO $ do
     ctx <- cairoCreateContext Nothing
     layout <- layoutEmpty ctx
-    layoutSetMarkup layout (Markup.unMarkup s)
+    layoutSetMarkup layout (Markup.unMarkup s) :: IO String
     layoutSetFontDescription layout (Just font)
     layoutSetEllipsize layout e
     layoutSetAlignment layout a
diff --git a/Bustle/UI.hs b/Bustle/UI.hs
index a78797e..9843b29 100644
--- a/Bustle/UI.hs
+++ b/Bustle/UI.hs
@@ -30,6 +30,7 @@ import Data.IORef
 import qualified Data.Set as Set
 import Data.List (intercalate)
 import Data.Time
+import qualified Data.Text as T
 import Data.Monoid (mempty)
 import Text.Printf
 
@@ -281,6 +282,7 @@ promptToSave wi = io $ do
     case mdetails of
         Just (RecordedLog tempFilePath) -> do
             let tempFileName = takeFileName tempFilePath
+                title :: String
                 title = printf (__ "Save log '%s' before closing?") tempFileName
             prompt <- messageDialogNew (Just (wiWindow wi))
                                        [DialogModal]
@@ -459,7 +461,7 @@ wiSetLogDetails :: WindowInfo
                 -> IO ()
 wiSetLogDetails wi logDetails = do
     writeIORef (wiLogDetails wi) (Just logDetails)
-    windowSetTitle (wiWindow wi) (printf (__ "%s - Bustle") (logWindowTitle logDetails))
+    windowSetTitle (wiWindow wi) (printf (__ "%s - Bustle") (logWindowTitle logDetails) :: String)
 
 setPage :: MonadIO io
         => WindowInfo
@@ -525,7 +527,7 @@ loadPixbuf :: FilePath -> IO (Maybe Pixbuf)
 loadPixbuf filename = do
   iconName <- getDataFileName $ "data/" ++ filename
   C.catch (fmap Just (pixbufNewFromFile iconName))
-          (\(GError _ _ msg) -> warn msg >> return Nothing)
+          (\(GError _ _ msg) -> warn (T.unpack msg) >> return Nothing)
 
 openDialogue :: Window -> B ()
 openDialogue window = embedIO $ \r -> do
diff --git a/Bustle/UI/Canvas.hs b/Bustle/UI/Canvas.hs
index 46c1582..5a28761 100644
--- a/Bustle/UI/Canvas.hs
+++ b/Bustle/UI/Canvas.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE OverloadedStrings #-}
 {-
 Bustle.UI.Canvas: displays diagrams
 Copyright © 2008–2012 Collabora Ltd.
@@ -58,7 +59,7 @@ canvasNew :: Eq a
           -> (Maybe a -> IO ())
           -> IO (Canvas a)
 canvasNew builder showBounds selectionChangedCb = do
-    layout <- builderGetObject builder castToLayout "diagramLayout"
+    layout <- builderGetObject builder castToLayout ("diagramLayout" :: String)
     idRef <- newIORef Nothing
     shapesRef <- newIORef []
     widthRef <- newIORef 0
diff --git a/Bustle/UI/DetailsView.hs b/Bustle/UI/DetailsView.hs
index 35e80d6..d1b9d96 100644
--- a/Bustle/UI/DetailsView.hs
+++ b/Bustle/UI/DetailsView.hs
@@ -55,7 +55,7 @@ addValue :: Table
          -> Int
          -> IO Label
 addValue table row = do
-    label <- labelNew Nothing
+    label <- labelNew (Nothing :: Maybe String)
     miscSetAlignment label 0 0
     labelSetEllipsize label EllipsizeStart
     labelSetSelectable label True
@@ -77,7 +77,7 @@ detailsViewNew = do
                 , tableColumnSpacing := 6
                 ]
 
-    title <- labelNew Nothing
+    title <- labelNew (Nothing :: Maybe String)
     miscSetAlignment title 0 0
     tableAttach table title 0 2 0 1 [Fill] [Fill] 0 0
 
diff --git a/Bustle/UI/FilterDialog.hs b/Bustle/UI/FilterDialog.hs
index 9560507..152931e 100644
--- a/Bustle/UI/FilterDialog.hs
+++ b/Bustle/UI/FilterDialog.hs
@@ -99,7 +99,7 @@ runFilterDialog parent names currentlyHidden = do
     nameStore <- makeStore names currentlyHidden
     sw <- makeView nameStore
 
-    instructions <- labelNew Nothing
+    instructions <- labelNew (Nothing :: Maybe String)
     widgetSetSizeRequest instructions 600 (-1)
     labelSetMarkup instructions
         (__ "Unticking a service hides its column in the diagram, \
diff --git a/Bustle/UI/Recorder.hs b/Bustle/UI/Recorder.hs
index 1e98a68..085eea2 100644
--- a/Bustle/UI/Recorder.hs
+++ b/Bustle/UI/Recorder.hs
@@ -27,6 +27,7 @@ import Control.Monad (when, liftM)
 import Control.Concurrent.MVar
 import qualified Data.Map as Map
 import Data.Monoid
+import qualified Data.Text as T
 import Control.Monad.State (runStateT)
 import Text.Printf
 
@@ -77,8 +78,7 @@ processBatch pendingRef n label incoming = do
                 -- message from the user's perspective.
                 i <- takeMVar n
                 let j = i + (length pending)
-                labelSetMarkup label $
-                    printf (__ "Logged <b>%u</b> messages…") j
+                labelSetMarkup label $ (printf (__ "Logged <b>%u</b> messages…") j :: String)
                 putMVar n j
 
                 incoming rr'
@@ -97,8 +97,8 @@ recorderRun filename mwindow incoming finished = C.handle newFailed $ do
     maybe (return ()) (windowSetTransientFor dialog) mwindow
     dialog `set` [ windowModal := True ]
 
-    label <- labelNew Nothing
-    labelSetMarkup label $ printf (__ "Logged <b>%u</b> messages…") (0 :: Int)
+    label <- labelNew (Nothing :: Maybe String)
+    labelSetMarkup label $ (printf (__ "Logged <b>%u</b> messages…") (0 :: Int) :: String)
     loaderStateRef <- newMVar Map.empty
     pendingRef <- newMVar []
     let updateLabel µs body = do
@@ -142,7 +142,7 @@ recorderRun filename mwindow incoming finished = C.handle newFailed $ do
     widgetShowAll dialog
   where
     newFailed (GError _ _ message) = do
-        displayError mwindow message Nothing
+        displayError mwindow (T.unpack message) Nothing
 
 recorderChooseFile :: FilePath
                    -> Maybe Window
diff --git a/bustle.cabal b/bustle.cabal
index 4ac107c..2d1f907 100644
--- a/bustle.cabal
+++ b/bustle.cabal
@@ -106,10 +106,10 @@ Executable bustle
                , directory
                , filepath
                , glib
-               , gtk >= 0.12.4
+               , gtk >= 0.13
                , hgettext >= 0.1.5
                , mtl
-               , pango
+               , pango >= 0.13
                , parsec
                , pcap
                , process
@@ -136,7 +136,7 @@ Executable test-monitor
                , dbus
                , directory
                , filepath
-               , gtk > 0.12
+               , gtk >= 0.13
                , glib
                , hgettext
                , mtl