diff --git a/marginaleffects/datagrid.py b/marginaleffects/datagrid.py
index 6fea645..9e84694 100644
--- a/marginaleffects/datagrid.py
+++ b/marginaleffects/datagrid.py
@@ -122,6 +122,7 @@ def datagridcf(model=None, newdata=None, **kwargs):
 
     if "rowid" not in newdata.columns:
         newdata = newdata.with_columns(pl.Series(range(newdata.shape[0])).alias("rowid"))
+    newdata = newdata.rename({"rowid" : "rowidcf"})
 
     # Create dataframe from kwargs
     dfs = [pl.DataFrame({k: v}) for k, v in kwargs.items()]
@@ -129,11 +130,10 @@ def datagridcf(model=None, newdata=None, **kwargs):
     # Perform cross join
     df_cross = reduce(lambda df1, df2: df1.join(df2, how='cross'), dfs)
 
-    result = newdata.join(df_cross, how = "cross")
+    # Drop would-be duplicates
+    newdata = newdata.drop(df_cross.columns)
 
-    # Create rowid and rowidcf
-    rowidcf = [i for i in range(newdata.shape[0]) for _ in range(result.select(pl.count()).item() // newdata.select(pl.count()).item())]
-    result = result.with_columns(pl.Series(rowidcf).alias("rowidcf"))
+    result = newdata.join(df_cross, how = "cross")
 
     result.datagrid_explicit = list(kwargs.keys())
 
diff --git a/tests/test_datagrid.py b/tests/test_datagrid.py
index c25b31e..18c45ab 100644
--- a/tests/test_datagrid.py
+++ b/tests/test_datagrid.py
@@ -19,4 +19,8 @@ def test_simple_grid():
 def test_cf():
     assert datagrid(newdata = mtcars, mpg = 32).shape[0] == 1
     assert datagridcf(newdata = mtcars, mpg = [30, 32]).shape[0] == 64
-    assert datagridcf(newdata = mtcars, mpg = [30, 32]).unique("rowidcf").shape[0] == 32
\ No newline at end of file
+    assert datagridcf(newdata = mtcars, mpg = 32, am = 0, hp = 100).shape[0] == 32
+    assert datagridcf(newdata = mtcars, am = [0, 1], hp = [100, 110, 120]).shape[0] == 192
+    assert datagridcf(newdata = mtcars, mpg = [30, 32]).unique("rowidcf").shape[0] == 32
+    assert set(datagridcf(newdata = mtcars, mpg = [30, 32]).columns) \
+        == {'gear', 'qsec', 'mpg', 'cyl', 'am', 'wt', 'vs', 'drat', 'rowidcf', 'disp', 'rownames', 'hp', 'carb'}