diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,16 @@
+concurrent-output (1.7.0) unstable; urgency=medium
+
+  * Simplified the RegionContent type; a region's content is now internally
+    always an STM action.
+  * This simplification fixed a bug that had prevented sometimes displaying
+    changes to InLine regions with STM actions for content. Now any changes
+    to TVars etc accessed by such STM actions will be noticed when waiting
+    on the parent region's content changing.
+  * Fix bug that caused double display of children of regions in some
+    circumstances.
+
+ -- Joey Hess <id@joeyh.name>  Mon, 09 Nov 2015 16:13:19 -0400
+
 concurrent-output (1.6.1) unstable; urgency=medium
 
   * Avoid cursorUpLine, which is not as portable as cursorUp.
diff --git a/System/Console/Regions.hs b/System/Console/Regions.hs
--- a/System/Console/Regions.hs
+++ b/System/Console/Regions.hs
@@ -66,6 +66,7 @@
 	ConsoleRegion,
 	RegionLayout(..),
 	ToRegionContent(..),
+	RegionContent(..),
 	LiftRegion(..),
 	-- * Initialization
 	displayConsoleRegions,
@@ -101,7 +102,6 @@
 	-- >		, show h
 	-- > 		]
 	-- >
-	RegionContent(..),
 	consoleWidth,
 	consoleHeight,
 	regionList,
@@ -163,9 +163,7 @@
 	, regionChildren :: TVar [ConsoleRegion]
 	}
 
-data RegionContent
-	= RegionContent (TVar Text) 
-	| RegionContentSTM (STM Text)
+newtype RegionContent = RegionContent (STM Text)
 
 -- | All the regions that are currently displayed on the screen.
 --
@@ -201,7 +199,7 @@
 	munge = pred
 #endif
 
--- | Get the height from the `consoleSize`
+-- | Get the height of the console.
 consoleHeight :: STM Int
 consoleHeight = Console.height <$> readTVar consoleSize
 
@@ -224,7 +222,7 @@
 
 -- | Values that can be displayed in a region.
 class ToRegionContent v where
-	toRegionContent :: v -> STM RegionContent
+	toRegionContent :: v -> RegionContent
 
 instance ToRegionContent String where
 	toRegionContent = fromOutput
@@ -232,15 +230,15 @@
 instance ToRegionContent Text where
 	toRegionContent = fromOutput
 
-fromOutput :: Outputable v => v -> STM RegionContent
-fromOutput v = RegionContent <$> newTVar (toOutput v)
+fromOutput :: Outputable v => v -> RegionContent
+fromOutput = RegionContent . pure . toOutput
 
 -- | Makes a STM action be run to get the content of a region.
 --
 -- Any change to the values that action reads will result in an immediate
 -- refresh of the display.
 instance ToRegionContent (STM Text) where
-	toRegionContent = pure . RegionContentSTM
+	toRegionContent = RegionContent
 
 -- | Sets the value of a console region. This will cause the
 -- console to be updated to display the new value.
@@ -256,18 +254,15 @@
 -- movement, will mess up the layouts of regions. Caveat emptor.
 setConsoleRegion :: (ToRegionContent v, LiftRegion m) => ConsoleRegion -> v -> m ()
 setConsoleRegion r v = liftRegion $
-	modifyRegion r $ const $ toRegionContent v
+	modifyRegion r $ const $ pure $ toRegionContent v
 
 -- | Appends a value to the current value of a console region.
 --
 -- > appendConsoleRegion progress "." -- add another dot to progress display
 appendConsoleRegion :: (Outputable v, LiftRegion m) => ConsoleRegion -> v -> m ()
 appendConsoleRegion r v = liftRegion $
-	modifyRegion r $ \rc -> case rc of
-		RegionContent cv -> do
-			modifyTVar' cv (<> toOutput v)
-			return rc
-		RegionContentSTM a -> return $ RegionContentSTM $ do
+	modifyRegion r $ \(RegionContent a) ->
+		return $ RegionContent $ do
 			t <- a
 			return (t <> toOutput v)
 
@@ -278,15 +273,11 @@
 	t <- readRegionContent rc
 	width <- consoleWidth
 	writeTVar (regionLines r) =<< calcRegionLines r t width
-	case regionLayout r of
-		Linear -> return ()
-		InLine p -> refreshRegion p
 	let r' = r { regionContent = rc }
 	writeTVar tv r'
 
 readRegionContent :: RegionContent -> STM Text
-readRegionContent (RegionContent t) = readTVar t
-readRegionContent (RegionContentSTM a) = a
+readRegionContent (RegionContent a) = a
 
 resizeRegion :: Width -> ConsoleRegion -> STM (R, [Text])
 resizeRegion width (ConsoleRegion tv) = do
@@ -319,20 +310,30 @@
 -- | Makes a new region, but does not add it to the display.
 newConsoleRegion :: (LiftRegion m) => ToRegionContent v => RegionLayout -> v -> m ConsoleRegion
 newConsoleRegion ly v = liftRegion $ do
-	rc <- newTVar mempty
 	rl <- newTVar mempty
 	rs <- newTVar mempty
 	let r = R
-		{ regionContent = RegionContent rc
+		{ regionContent = RegionContent $ return mempty
 		, regionRender = pure
 		, regionLines = rl
 		, regionLayout = ly
 		, regionChildren = rs
 		}
 	h <- ConsoleRegion <$> newTVar r
+	displayChildren h
 	setConsoleRegion h v
 	return h
 
+displayChildren :: ConsoleRegion -> STM ()
+displayChildren p@(ConsoleRegion tv) = tuneDisplay p $ \t -> do
+	children <- readTVar . regionChildren =<< readTVar tv
+	ct <- T.concat <$> mapM getc children
+	return $ t <> ct
+  where
+	getc (ConsoleRegion cv) = do
+		c <- readTVar cv
+		regionRender c =<< readRegionContent (regionContent c)
+
 -- | Closes a console region. Once closed, the region is removed from the
 -- display.
 closeConsoleRegion :: LiftRegion m => ConsoleRegion -> m ()
@@ -373,6 +374,9 @@
 -- > tuneDisplay myregion $ pure . T.reverse
 --
 -- Note that repeated calls to tuneDisplay are cumulative.
+--
+-- Normally, the STM action should avoid retrying, as that would
+-- block all display updates.
 tuneDisplay :: LiftRegion m => ConsoleRegion -> (Text -> STM Text) -> m ()
 tuneDisplay cr@(ConsoleRegion tv) renderer = liftRegion $ do
 	r <- readTVar tv
@@ -380,7 +384,7 @@
 	let r' = r { regionRender = rr }
 	writeTVar tv r'
 	refreshRegion cr
-	
+
 refreshRegion :: ConsoleRegion -> STM ()
 refreshRegion (ConsoleRegion tv) = do
 	r <- readTVar tv
@@ -388,24 +392,12 @@
 	t <- readRegionContent (regionContent r)
 	writeTVar (regionLines r) =<< calcRegionLines r t width
 
-displayChildren :: ConsoleRegion -> STM ()
-displayChildren p@(ConsoleRegion tv) = tuneDisplay p $ \t -> do
-	children <- readTVar . regionChildren =<< readTVar tv
-	ct <- T.concat <$> mapM getc children
-	return $ t <> ct
-  where
-	getc (ConsoleRegion cv) = do
-		c <- readTVar cv
-		regionRender c =<< readRegionContent (regionContent c)
-
 addChild :: ConsoleRegion -> ConsoleRegion -> STM ()
-addChild child parent@(ConsoleRegion pv) = do
+addChild child _parent@(ConsoleRegion pv) = do
 	cv <- regionChildren <$> readTVar pv
 	children <- readTVar cv
 	let !children' = filter (/= child) children ++ [child]
 	writeTVar cv children'
-	when (null children) $
-		displayChildren parent
 
 removeChild :: ConsoleRegion -> ConsoleRegion -> STM ()
 removeChild child _parent@(ConsoleRegion pv) = do
@@ -529,14 +521,12 @@
 		retry
 	return (orighandles, rs, newlines)
   where
-	getr (r, ols) = case regionContent r of
-		RegionContent _ -> reverse <$> readTVar (regionLines r)
-		RegionContentSTM a -> do
-			c <- a
-			ls <- reverse <$> calcRegionLines r c width
-			when (ls /= ols) $
-				writeTVar (regionLines r) ls
-			return ls
+	getr (r, ols) = do
+		c <- readRegionContent (regionContent r)
+		ls <- reverse <$> calcRegionLines r c width
+		when (ls /= ols) $
+			writeTVar (regionLines r) ls
+		return ls
 
 -- This is not an optimal screen update like curses can do, but it's
 -- pretty efficient, most of the time!
diff --git a/concurrent-output.cabal b/concurrent-output.cabal
--- a/concurrent-output.cabal
+++ b/concurrent-output.cabal
@@ -1,5 +1,5 @@
 Name: concurrent-output
-Version: 1.6.1
+Version: 1.7.0
 Cabal-Version: >= 1.8
 License: BSD2
 Maintainer: Joey Hess <id@joeyh.name>
diff --git a/stmdemo.hs b/stmdemo.hs
--- a/stmdemo.hs
+++ b/stmdemo.hs
@@ -20,8 +20,8 @@
 infoRegion = do
 	r <- openConsoleRegion Linear
 	setConsoleRegion r $ do
-	 	w <- readTVar consoleWidth
-	 	h <- readTVar consoleHeight
+	 	w <- consoleWidth
+	 	h <- consoleHeight
 		regions <- readTMVar regionList
  		return $ T.pack $ unwords
  			[ "size:"