diff --git a/tests/AcDream.App.Tests/UI/UiRootInputTests.cs b/tests/AcDream.App.Tests/UI/UiRootInputTests.cs
index 89123682..9f326919 100644
--- a/tests/AcDream.App.Tests/UI/UiRootInputTests.cs
+++ b/tests/AcDream.App.Tests/UI/UiRootInputTests.cs
@@ -173,6 +173,27 @@ public class UiRootInputTests
         Assert.Equal(70f, x);
     }
 
+    [Fact]
+    public void ResizeRect_Bottom_ClampsToMaxH()
+    {
+        // dy=1000 on a 50-tall window with maxH=128 → height clamps to 128, origin unchanged.
+        var (_, y, _, h) = UiRoot.ResizeRect(10, 20, 100, 50,
+            ResizeEdges.Bottom, dx: 0, dy: 1000, minW: 40, minH: 40, maxW: float.MaxValue, maxH: 128f);
+        Assert.Equal(128f, h);
+        Assert.Equal(20f, y);
+    }
+
+    [Fact]
+    public void ResizeRect_Top_ClampsToMaxH()
+    {
+        // Drag the top edge UP by 1000 on a 50-tall window with maxH=128 → height clamps to 128,
+        // origin shifts so the bottom edge (70) stays put → y = 20 + 50 - 128.
+        var (_, y, _, h) = UiRoot.ResizeRect(10, 20, 100, 50,
+            ResizeEdges.Top, dx: 0, dy: -1000, minW: 40, minH: 40, maxW: float.MaxValue, maxH: 128f);
+        Assert.Equal(128f, h);
+        Assert.Equal(20f + 50f - 128f, y);
+    }
+
     [Fact]
     public void HitEdges_DetectsCornerAndInteriorNone()
     {