diff --git a/render-wasm/src/render.rs b/render-wasm/src/render.rs
index b840563f4f..cfc3ed1a0f 100644
--- a/render-wasm/src/render.rs
+++ b/render-wasm/src/render.rs
@@ -986,7 +986,12 @@ impl RenderState {
     }
 
     pub fn set_background_color(&mut self, color: skia::Color) {
+        if self.background_color == color {
+            return;
+        }
         self.background_color = color;
+        // Tiles bake the background in; old atlas pixels would show on pan/zoom.
+        self.surfaces.atlas.clear();
     }
 
     pub fn set_preview_mode(&mut self, enabled: bool) {
diff --git a/render-wasm/src/render/surfaces.rs b/render-wasm/src/render/surfaces.rs
index 761b2d02d6..9d07a6362e 100644
--- a/render-wasm/src/render/surfaces.rs
+++ b/render-wasm/src/render/surfaces.rs
@@ -185,6 +185,12 @@ impl DocAtlas {
         self.size.width <= 0 || self.size.height <= 0
     }
 
+    /// Drops all atlas content while keeping its allocation and placement.
+    pub fn clear(&mut self) {
+        self.surface.canvas().clear(skia::Color::TRANSPARENT);
+        self.tile_doc_rects.clear();
+    }
+
     /// Sets the document-space bounds used to clamp atlas updates.
     /// Pass `None` to disable clamping.
     pub fn set_doc_bounds(&mut self, bounds: Option<skia::Rect>) {