diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,21 @@
 
 `gridtables` uses [PVP Versioning][].
 
+## gridtables-0.1.1.1
+
+-   Fix a bug in computing table alignments with colspans (#3).
+    If a header cell with colspans has an alignment, that
+    alignment is given to all the columns spanned instead of
+    just the first.
+
+-   Bump version bound for doclayout.
+
+-   Remove call to partial function `tail`.
+
+-   Allow containers 0.8.
+
+-   Fix list of tested GHC versions in cabal file.
+
 ## gridtables-0.1.1.0
 
 Released 2025-09-22.
diff --git a/gridtables.cabal b/gridtables.cabal
--- a/gridtables.cabal
+++ b/gridtables.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.4
 name:                gridtables
-version:             0.1.1.0
+version:             0.1.1.1
 synopsis:            Parser for reStructuredText-style grid tables.
 description:         Provides a parser for plain-text representations of
                      tables. This package supports table headers, cells
@@ -12,15 +12,19 @@
 license-file:        LICENSE
 author:              Albert Krewinkel
 maintainer:          Albert Krewinkel <albert@zeitkraut.de>
-copyright:           © 2022-2023 Posit Software, PBC
+copyright:           © 2022-2026 Posit Software, PBC
 category:            Text
 extra-doc-files:     README.md
                    , CHANGELOG.md
-tested-with:         GHC == 8.6.5
-                     GHC == 8.8.4
-                     GHC == 8.10.7
-                     GHC == 9.0.2
-                     GHC == 9.2.2
+tested-with:         GHC == 8.10.7
+                   , GHC == 9.0
+                   , GHC == 9.2
+                   , GHC == 9.4
+                   , GHC == 9.6
+                   , GHC == 9.8
+                   , GHC == 9.10
+                   , GHC == 9.12
+                   , GHC == 9.14
 
 source-repository head
   type:                git
@@ -56,8 +60,8 @@
 library
   import:              common-options
   hs-source-dirs:      src
-  build-depends:       containers            >= 0.6      && < 0.8
-                     , doclayout             >= 0.4      && < 0.6
+  build-depends:       containers            >= 0.6      && < 0.9
+                     , doclayout             >= 0.4      && < 0.7
   exposed-modules:     Text.GridTable
                      , Text.GridTable.ArrayTable
                      , Text.GridTable.Parse
diff --git a/src/Text/GridTable/Trace.hs b/src/Text/GridTable/Trace.hs
--- a/src/Text/GridTable/Trace.hs
+++ b/src/Text/GridTable/Trace.hs
@@ -27,7 +27,7 @@
 import Data.Array.ST
 import Data.Function (on)
 import Data.List (foldl')
-import Data.Maybe (fromMaybe)
+import Data.Maybe (fromMaybe, listToMaybe)
 import Data.Set (Set)
 import Data.Text (Text)
 import Text.DocLayout (charWidth, realLength)
@@ -411,14 +411,19 @@
       colseps = Set.toAscList $ gridColSeps traceInfo
       rowindex = Map.fromList $ zip rowseps [1..]
       colindex = Map.fromList $ zip colseps [1..]
-      colwidths = [ b - a - 1 | (b, a) <- zip (tail colseps) colseps ]
+      colwidths = [ b - a - 1 | (b, a) <- zip (drop 1 colseps) colseps ]
+      alignSpecs = case partSeps of
+                     partSep:_ -> partSepColSpec partSep
+                     []        -> fromMaybe [] colSpecsFirstLine
+      -- A segment of the alignment line may span multiple columns;
+      -- each column gets the alignment of the segment containing it.
+      alignFor (left, right) = fromMaybe AlignDefault $ listToMaybe
+        [ colAlign cs | cs <- alignSpecs
+                      , colStart cs - 1 <= left
+                      , right <= colEnd cs ]
       colSpecs = zip
-                 (map colAlign
-                   (case partSeps of
-                       partSep:_ -> partSepColSpec partSep
-                       []        -> fromMaybe [] colSpecsFirstLine)
-                   ++ repeat AlignDefault)
-                 (map fromCharCol colwidths)
+                  (map alignFor (zip colseps (drop 1 colseps)))
+                  (map fromCharCol colwidths)
       lastCol = ColIndex (length colwidths)
       mlastLine = Set.lookupMax (gridRowSeps traceInfo)
       tableHead = case partSeps of
diff --git a/test/test-gridtables.hs b/test/test-gridtables.hs
--- a/test/test-gridtables.hs
+++ b/test/test-gridtables.hs
@@ -528,6 +528,42 @@
                      , [Cell "3" 1 1]
                      ]
     ]
+  , testGroup "markers spanning multiple columns"
+    [ testCase "marker in first line" $
+      let gt = T.unlines
+               [ "+:------------:+---------------:+"
+               , "| Heading 1    | Heading 2      |"
+               , "+---+----+-----+----+------+----+"
+               , "| A | B  | C   | D  |  E   | F  |"
+               , "+---+----+-----+----+------+----+"
+               ]
+      in arrayTableColSpecs <$> parse' gridTable gt @?=
+         Right (listArray (1, 6)
+                [ (AlignCenter, 3)
+                , (AlignCenter, 4)
+                , (AlignCenter, 5)
+                , (AlignRight, 4)
+                , (AlignRight, 6)
+                , (AlignRight, 4)
+                ])
+
+    , testCase "marker in part separator" $
+      let gt = T.unlines
+               [ "+-------------+-------+"
+               , "| head        | c     |"
+               , "+:===========:+======:+"
+               , "| ab          | c     |"
+               , "+------+------+-------+"
+               , "| a    | b    | c     |"
+               , "+------+------+-------+"
+               ]
+      in arrayTableColSpecs <$> parse' gridTable gt @?=
+         Right (listArray (1, 3)
+                [ (AlignCenter, 6)
+                , (AlignCenter, 6)
+                , (AlignRight, 7)
+                ])
+    ]
   ]
 
 defaultAlign :: [Int] -> Array ColIndex (Alignment, Int)