diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index 3b9f02630..960890009 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -384,7 +384,6 @@ func (i *Image) DrawTriangles(img *Image, vertices []float32, indices []uint16,
 	if (img != nil && (img.stale || img.volatile)) || i.screen || !needsRestoring() || i.volatile {
 		i.makeStale()
 	} else {
-		// TODO: Need to copy uniform variables?
 		i.appendDrawTrianglesHistory(img, vertices, indices, colorm, mode, filter, address, shader, uniforms)
 	}
 	var s *graphicscommand.Shader
@@ -502,7 +501,7 @@ func (i *Image) resolveStale() error {
 	return i.readPixelsFromGPU()
 }
 
-// dependsOn returns a boolean value indicating whether the image depends on target.
+// dependsOn reports whether the image depends on target.
 func (i *Image) dependsOn(target *Image) bool {
 	for _, c := range i.drawTrianglesHistory {
 		if c.image == target {
diff --git a/internal/restorable/images.go b/internal/restorable/images.go
index c56dfa1fa..26e770d0b 100644
--- a/internal/restorable/images.go
+++ b/internal/restorable/images.go
@@ -150,10 +150,9 @@ func (i *images) resolveStaleImages() error {
 
 // makeStaleIfDependingOn makes all the images stale that depend on target.
 //
-// When target is changed, all images depending on target can't be restored with target.
+// When target is modified, all images depending on target can't be restored with target.
 // makeStaleIfDependingOn is called in such situation.
 func (i *images) makeStaleIfDependingOn(target *Image) {
-	// Avoid defer for performance
 	i.makeStaleIfDependingOnImpl(target)
 }
 
diff --git a/internal/restorable/shader_test.go b/internal/restorable/shader_test.go
index d1adaea49..24dd41a68 100644
--- a/internal/restorable/shader_test.go
+++ b/internal/restorable/shader_test.go
@@ -94,3 +94,45 @@ func TestShaderChain(t *testing.T) {
 		}
 	}
 }
+
+func TestShaderMultipleSources(t *testing.T) {
+	if !graphicscommand.IsShaderAvailable() {
+		t.Skip("shader is not available on this environment")
+	}
+
+	srcs := make([]*Image, 3)
+	for i := range srcs {
+		srcs[i] = NewImage(1, 1, false)
+	}
+	srcs[0].ReplacePixels([]byte{0x40, 0, 0, 0xff}, 0, 0, 1, 1)
+	srcs[1].ReplacePixels([]byte{0, 0x80, 0, 0xff}, 0, 0, 1, 1)
+	srcs[2].ReplacePixels([]byte{0, 0, 0xc0, 0xff}, 0, 0, 1, 1)
+
+	dst := NewImage(1, 1, false)
+
+	ir := etesting.ShaderProgramImages(3)
+	s := NewShader(&ir)
+	us := map[int]interface{}{
+		0: []float32{1, 1},
+		1: srcs[0],
+		2: srcs[1],
+		5: srcs[2],
+	}
+	dst.DrawTriangles(nil, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), nil, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressClampToZero, s, us)
+
+	// Clear one of the sources after DrawTriangles. dst should not be affected.
+	srcs[0].Fill(color.RGBA{})
+
+	if err := ResolveStaleImages(); err != nil {
+		t.Fatal(err)
+	}
+	if err := RestoreIfNeeded(); err != nil {
+		t.Fatal(err)
+	}
+
+	want := color.RGBA{0x40, 0x80, 0xc0, 0xff}
+	got := pixelsToColor(dst.BasePixelsForTesting(), 0, 0)
+	if !sameColors(got, want, 1) {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}