diff --git a/ui/context_multi_native_test.go b/ui/context_multi_native_test.go
new file mode 100644
index 00000000..7c46ddc1
--- /dev/null
+++ b/ui/context_multi_native_test.go
@@ -0,0 +1,139 @@
+//go:build !js || !wasm
+
+package ui_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/monstercameron/GoWebComponents/internal/platform/mockdom"
+	"github.com/monstercameron/GoWebComponents/internal/runtime"
+)
+
+// Deepens the ReactNewContext port: multiple independent contexts coexist; a
+// single consumer can read several; updating one context updates only the
+// consumers of that context.
+func TestMultipleIndependentContexts(t *testing.T) {
+	adapter := mockdom.NewMockDOMAdapter()
+	rt := runtime.NewRuntime(runtime.Config{DOMAdapter: adapter, Reset: true})
+	root := adapter.CreateElement("div")
+
+	parseDesc1 := runtime.NewContextDescriptor("D1")
+	parseDesc2 := runtime.NewContextDescriptor("D2")
+	parseProvider1 := runtime.NewContextProviderType(parseDesc1)
+	parseProvider2 := runtime.NewContextProviderType(parseDesc2)
+
+	// A consumer that reads both contexts.
+	parseBothConsumer := func() *runtime.Element {
+		return runtime.CreateElement("span", map[string]any{"data-c": "both"},
+			fmt.Sprintf("%v|%v", runtime.GoUseContextValue(parseDesc1), runtime.GoUseContextValue(parseDesc2)))
+	}
+	// A consumer that reads only context 2.
+	parseSecondConsumer := func() *runtime.Element {
+		return runtime.CreateElement("span", map[string]any{"data-c": "second"},
+			fmt.Sprint(runtime.GoUseContextValue(parseDesc2)))
+	}
+
+	textByMarker := func(parseMarker string) string {
+		var parseWalk func(parseN *mockdom.MockDOMNode) string
+		parseWalk = func(parseN *mockdom.MockDOMNode) string {
+			if parseN == nil {
+				return ""
+			}
+			if parseN.Attrs["data-c"] == parseMarker {
+				return parseN.TextContent
+			}
+			for _, parseC := range parseN.Children {
+				if parseR := parseWalk(parseC); parseR != "" {
+					return parseR
+				}
+			}
+			return ""
+		}
+		for _, parseK := range adapter.GetChildren(root) {
+			if parseN, parseOk := parseK.(*mockdom.MockDOMNode); parseOk {
+				if parseR := parseWalk(parseN); parseR != "" {
+					return parseR
+				}
+			}
+		}
+		return ""
+	}
+
+	var parseSet1 func(any)
+	parseApp := func() *runtime.Element {
+		parseGet1, parseSetter1 := runtime.GoUseState(rt, "A")
+		parseSet1 = parseSetter1
+		return runtime.CreateElementOwned(parseProvider1, map[string]any{"value": parseGet1()},
+			runtime.CreateElementOwned(parseProvider2, map[string]any{"value": "B"},
+				runtime.CreateElement("div", map[string]any{},
+					runtime.CreateElement(parseBothConsumer, map[string]any{}),
+					runtime.CreateElement(parseSecondConsumer, map[string]any{}))))
+	}
+
+	rt.RenderInto(root, runtime.CreateElement(parseApp, map[string]any{}))
+	if parseGot := textByMarker("both"); parseGot != "A|B" {
+		t.Fatalf("both-consumer = %q, want A|B", parseGot)
+	}
+	if parseGot := textByMarker("second"); parseGot != "B" {
+		t.Fatalf("second-consumer = %q, want B", parseGot)
+	}
+
+	// Updating context 1 updates the both-consumer; the second-consumer (context 2
+	// only) is unaffected by the value change.
+	parseSet1("A2")
+	if parseGot := textByMarker("both"); parseGot != "A2|B" {
+		t.Errorf("after update both-consumer = %q, want A2|B", parseGot)
+	}
+	if parseGot := textByMarker("second"); parseGot != "B" {
+		t.Errorf("after update second-consumer = %q, want B (unchanged)", parseGot)
+	}
+}
+
+// Same context used at two nesting levels: the inner provider value shadows the
+// outer one for the inner consumer, while a consumer between the two providers
+// still sees the outer value.
+func TestSameContextTwoLevels(t *testing.T) {
+	adapter := mockdom.NewMockDOMAdapter()
+	rt := runtime.NewRuntime(runtime.Config{DOMAdapter: adapter, Reset: true})
+	root := adapter.CreateElement("div")
+
+	parseDesc := runtime.NewContextDescriptor("DEFAULT")
+	parseProvider := runtime.NewContextProviderType(parseDesc)
+	parseConsumer := func() *runtime.Element {
+		return runtime.CreateElement("span", map[string]any{}, fmt.Sprint(runtime.GoUseContextValue(parseDesc)))
+	}
+
+	rt.RenderInto(root, runtime.CreateElementOwned(parseProvider, map[string]any{"value": "OUTER"},
+		runtime.CreateElement("div", map[string]any{},
+			runtime.CreateElement(parseConsumer, map[string]any{}), // sees OUTER
+			runtime.CreateElementOwned(parseProvider, map[string]any{"value": "INNER"},
+				runtime.CreateElement(parseConsumer, map[string]any{}))))) // sees INNER
+
+	parseOut, _ := concatTreeText(t, adapter, root)
+	if parseOut != "OUTERINNER" {
+		t.Errorf("two-level same context = %q, want OUTERINNER", parseOut)
+	}
+}
+
+// concatTreeText concatenates all span text under root in document order.
+func concatTreeText(t *testing.T, adapter *mockdom.MockDOMAdapter, root runtime.DOMNode) (string, error) {
+	t.Helper()
+	var parseOut string
+	var parseWalk func(parseN *mockdom.MockDOMNode)
+	parseWalk = func(parseN *mockdom.MockDOMNode) {
+		if parseN == nil {
+			return
+		}
+		parseOut += parseN.TextContent
+		for _, parseC := range parseN.Children {
+			parseWalk(parseC)
+		}
+	}
+	for _, parseK := range adapter.GetChildren(root) {
+		if parseN, parseOk := parseK.(*mockdom.MockDOMNode); parseOk {
+			parseWalk(parseN)
+		}
+	}
+	return parseOut, nil
+}