diff --git a/rewrite-inspector.cabal b/rewrite-inspector.cabal
--- a/rewrite-inspector.cabal
+++ b/rewrite-inspector.cabal
@@ -1,5 +1,5 @@
 name: rewrite-inspector
-version: 0.1.0.9
+version: 0.1.0.10
 cabal-version: >=1.10
 build-type: Simple
 license: BSD3
@@ -35,7 +35,7 @@
                       hashable      >= 1.2.1.0  && < 1.3,
                       containers    >= 0.5.0.0  && < 0.7,
                       brick         == 0.46,
-                      vty           >= 5.23.1,
+                      vty           >= 5.26,
                       prettyprinter >= 1.2.0.1  && < 2.0,
                       text,
                       microlens     >= 0.3.0.0,
diff --git a/src/BrickUI.hs b/src/BrickUI.hs
--- a/src/BrickUI.hs
+++ b/src/BrickUI.hs
@@ -15,7 +15,7 @@
 
 import System.Environment     (getArgs)
 import Control.Applicative    ((<|>))
-import Control.Monad          (void, (>>))
+import Control.Monad          (void)
 import Control.Monad.Fail     (MonadFail (..))
 import Control.Monad.IO.Class (liftIO)
 
@@ -196,7 +196,7 @@
 lookupSize :: EventM Name (VizStates term -> VizStates term)
 lookupSize = do
   out    <- V.outputIface <$> B.getVtyHandle
-  (w, h) <- V.displayBounds out
+  (w, h) <- liftIO (V.displayBounds out)
   return $ (width .~ w) . (height .~ h)
 
 -- | Update number of occurrences of searched string in both viewports.