diff --git a/scripts/lib/upstream-patches.mjs b/scripts/lib/upstream-patches.mjs
index 7b9608f..a4156a1 100644
--- a/scripts/lib/upstream-patches.mjs
+++ b/scripts/lib/upstream-patches.mjs
@@ -26,7 +26,7 @@ export async function patchUpstreamApp(stageAppDir) {
 
   const mainBundlePath = path.join(buildDir, mainBundleName);
   const source = await fs.readFile(mainBundlePath, "utf8");
-  const patched = patchLinuxOpenTargetsSource(source);
+  const patched = patchUpstreamMainSource(source);
 
   if (patched === source) {
     return;
@@ -35,6 +35,15 @@ export async function patchUpstreamApp(stageAppDir) {
   await fs.writeFile(mainBundlePath, patched);
 }
 
+export function patchUpstreamMainSource(source) {
+  let patched = source;
+
+  patched = patchLinuxOpenTargetsSource(patched);
+  patched = patchDisableTransparencySource(patched);
+
+  return patched;
+}
+
 export function patchLinuxOpenTargetsSource(source) {
   let patched = source;
 
@@ -54,6 +63,74 @@ export function patchLinuxOpenTargetsSource(source) {
   return patched;
 }
 
+export function patchDisableTransparencySource(source) {
+  let patched = source;
+
+  patched = patchLinuxWindowBackground(patched);
+  patched = patchLinuxWindowTransparency(patched);
+
+  return patched;
+}
+
+function patchLinuxWindowBackground(source) {
+  if (
+    /backgroundColor:[A-Za-z_$][\w$]*===`linux`\?\([A-Za-z_$][\w$]*\?[A-Za-z_$][\w$]*:[A-Za-z_$][\w$]*\):[A-Za-z_$][\w$]*,backgroundMaterial:null/.test(source)
+  ) {
+    return source;
+  }
+
+  const match = source.match(
+    /function ([A-Za-z_$][\w$]*)\(\{platform:([A-Za-z_$][\w$]*),appearance:([A-Za-z_$][\w$]*),opaqueWindowsEnabled:([A-Za-z_$][\w$]*),prefersDarkColors:([A-Za-z_$][\w$]*)\}\)\{return \4&&!([A-Za-z_$][\w$]*)\(\3\)&&\(\2===`darwin`\|\|\2===`win32`\)\?\{backgroundColor:\5\?([A-Za-z_$][\w$]*):([A-Za-z_$][\w$]*),backgroundMaterial:\2===`win32`\?`none`:null\}:\2===`win32`&&!\6\(\3\)\?\{backgroundColor:([A-Za-z_$][\w$]*),backgroundMaterial:`mica`\}:\{backgroundColor:([A-Za-z_$][\w$]*),backgroundMaterial:null\}\}/
+  );
+
+  if (!match) {
+    throw new Error("Unable to apply upstream patch; missing window background helper");
+  }
+
+  const [
+    anchor,
+    ,
+    platformVar,
+    ,
+    ,
+    prefersDarkVar,
+    ,
+    darkColorVar,
+    lightColorVar,
+    ,
+    fallbackColorVar
+  ] = match;
+  const fallback = `{backgroundColor:${fallbackColorVar},backgroundMaterial:null}`;
+  const replacement = anchor.replace(
+    fallback,
+    `{backgroundColor:${platformVar}===\`linux\`?(${prefersDarkVar}?${darkColorVar}:${lightColorVar}):${fallbackColorVar},backgroundMaterial:null}`
+  );
+
+  return replaceOnce(source, anchor, replacement);
+}
+
+function patchLinuxWindowTransparency(source) {
+  if (/transparent:[A-Za-z_$][\w$]*===`linux`\?!1:[A-Za-z_$][\w$]*,hasShadow:/.test(source)) {
+    return source;
+  }
+
+  const match = source.match(
+    /function ([A-Za-z_$][\w$]*)\(\{alwaysOnTop:([A-Za-z_$][\w$]*),hasShadow:([A-Za-z_$][\w$]*)=!0,platform:([A-Za-z_$][\w$]*),resizable:([A-Za-z_$][\w$]*),thickFrame:([A-Za-z_$][\w$]*),transparent:([A-Za-z_$][\w$]*)=!0\}\)\{return\{frame:!1,transparent:\7,hasShadow:\3,/
+  );
+
+  if (!match) {
+    throw new Error("Unable to apply upstream patch; missing window transparency helper");
+  }
+
+  const [anchor, , , shadowVar, platformVar, , , transparentVar] = match;
+  const replacement = anchor.replace(
+    `transparent:${transparentVar},hasShadow:${shadowVar},`,
+    `transparent:${platformVar}===\`linux\`?!1:${transparentVar},hasShadow:${shadowVar},`
+  );
+
+  return replaceOnce(source, anchor, replacement);
+}
+
 function patchOpenTargetMap(source) {
   if (source.includes("appPath:process.platform===`linux`")) {
     return source;
diff --git a/test/upstream-patches.test.mjs b/test/upstream-patches.test.mjs
index 4972cc6..5096793 100644
--- a/test/upstream-patches.test.mjs
+++ b/test/upstream-patches.test.mjs
@@ -1,7 +1,10 @@
 import test from "node:test";
 import assert from "node:assert/strict";
 
-import { patchLinuxOpenTargetsSource } from "../scripts/lib/upstream-patches.mjs";
+import {
+  patchDisableTransparencySource,
+  patchLinuxOpenTargetsSource
+} from "../scripts/lib/upstream-patches.mjs";
 
 test("patchLinuxOpenTargetsSource adds Linux editor targets and exposes app paths", () => {
   const source = [
@@ -109,3 +112,33 @@ test("patchLinuxOpenTargetsSource preserves native target spread variable", () =
   );
   assert.match(patched, /\}\)\),\.\.\.h\]/);
 });
+
+test("patchDisableTransparencySource disables Linux BrowserWindow transparency and background", () => {
+  const source = [
+    "function A2(e){return e===`avatarOverlay`||e===`browserCommentPopup`}",
+    "function I2({platform:e,appearance:t,opaqueWindowsEnabled:n,prefersDarkColors:r}){return n&&!A2(t)&&(e===`darwin`||e===`win32`)?{backgroundColor:r?a2:o2,backgroundMaterial:e===`win32`?`none`:null}:e===`win32`&&!A2(t)?{backgroundColor:i2,backgroundMaterial:`mica`}:{backgroundColor:i2,backgroundMaterial:null}}",
+    "function R2({alwaysOnTop:e,hasShadow:t=!0,platform:n,resizable:r,thickFrame:i,transparent:a=!0}){return{frame:!1,transparent:a,hasShadow:t,resizable:r,minimizable:!1,maximizable:!1,fullscreenable:!1,skipTaskbar:!0,...e?{alwaysOnTop:!0}:{},...n===`win32`?{accentColor:!1,roundedCorners:!1,...i==null?{}:{thickFrame:i}}:{},...n===`darwin`?{type:`panel`}:{}}}",
+    "function z2({appearance:e,platform:n}){switch(e){case`browserCommentPopup`:return R2({hasShadow:!1,platform:n,resizable:!1,thickFrame:!1,transparent:!0});case`avatarOverlay`:return R2({platform:n,resizable:!1})}}"
+  ].join(";");
+
+  const patched = patchDisableTransparencySource(source);
+
+  assert.match(patched, /backgroundColor:e===`linux`\?\(r\?a2:o2\):i2,backgroundMaterial:null/);
+  assert.doesNotMatch(patched, /\{backgroundColor:i2,backgroundMaterial:null\}/);
+  assert.match(patched, /transparent:n===`linux`\?!1:a,hasShadow:t/);
+  assert.doesNotMatch(patched, /return\{frame:!1,transparent:a,hasShadow:t/);
+});
+
+test("patchDisableTransparencySource is idempotent", () => {
+  const source = [
+    "function A2(e){return e===`avatarOverlay`||e===`browserCommentPopup`}",
+    "function I2({platform:e,appearance:t,opaqueWindowsEnabled:n,prefersDarkColors:r}){return n&&!A2(t)&&(e===`darwin`||e===`win32`)?{backgroundColor:r?a2:o2,backgroundMaterial:e===`win32`?`none`:null}:e===`win32`&&!A2(t)?{backgroundColor:i2,backgroundMaterial:`mica`}:{backgroundColor:i2,backgroundMaterial:null}}",
+    "function R2({alwaysOnTop:e,hasShadow:t=!0,platform:n,resizable:r,thickFrame:i,transparent:a=!0}){return{frame:!1,transparent:a,hasShadow:t,resizable:r,minimizable:!1,maximizable:!1,fullscreenable:!1,skipTaskbar:!0,...e?{alwaysOnTop:!0}:{},...n===`win32`?{accentColor:!1,roundedCorners:!1,...i==null?{}:{thickFrame:i}}:{},...n===`darwin`?{type:`panel`}:{}}}",
+    "function z2({appearance:e,platform:n}){switch(e){case`browserCommentPopup`:return R2({hasShadow:!1,platform:n,resizable:!1,thickFrame:!1,transparent:!0});case`avatarOverlay`:return R2({platform:n,resizable:!1})}}"
+  ].join(";");
+
+  const patched = patchDisableTransparencySource(source);
+  const repatched = patchDisableTransparencySource(patched);
+
+  assert.equal(repatched, patched);
+});