diff --git a/Sources/AppDelegate.swift b/Sources/AppDelegate.swift
index 155ecfc9..63db90ac 100644
--- a/Sources/AppDelegate.swift
+++ b/Sources/AppDelegate.swift
@@ -991,10 +991,15 @@ func browserOmnibarShouldSubmitOnReturn(flags: NSEvent.ModifierFlags) -> Bool {
 
 func shouldDispatchBrowserReturnViaFirstResponderKeyDown(
     keyCode: UInt16,
-    firstResponderIsBrowser: Bool
+    firstResponderIsBrowser: Bool,
+    flags: NSEvent.ModifierFlags
 ) -> Bool {
     guard firstResponderIsBrowser else { return false }
-    return keyCode == 36 || keyCode == 76
+    guard keyCode == 36 || keyCode == 76 else { return false }
+    // Keep browser Return forwarding narrow: only plain/Shift Return should be
+    // treated as submit-intent. Command-modified Return is reserved for app shortcuts
+    // like Toggle Pane Zoom (Cmd+Shift+Enter).
+    return browserOmnibarShouldSubmitOnReturn(flags: flags)
 }
 
 func shouldToggleMainWindowFullScreenForCommandControlFShortcut(
@@ -8462,7 +8467,8 @@ private extension NSWindow {
         // mark handled to avoid the AppKit alert sound path.
         if shouldDispatchBrowserReturnViaFirstResponderKeyDown(
             keyCode: event.keyCode,
-            firstResponderIsBrowser: firstResponderWebView != nil
+            firstResponderIsBrowser: firstResponderWebView != nil,
+            flags: event.modifierFlags
         ) {
             // Forwarding keyDown can re-enter performKeyEquivalent in WebKit/AppKit internals.
             // On re-entry, fall back to normal dispatch to avoid an infinite loop.
diff --git a/cmuxTests/CmuxWebViewKeyEquivalentTests.swift b/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
index dc2ecb6f..cc75f384 100644
--- a/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
+++ b/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
@@ -1988,7 +1988,8 @@ final class BrowserReturnKeyDownRoutingTests: XCTestCase {
         XCTAssertTrue(
             shouldDispatchBrowserReturnViaFirstResponderKeyDown(
                 keyCode: 36,
-                firstResponderIsBrowser: true
+                firstResponderIsBrowser: true,
+                flags: []
             )
         )
     }
@@ -1997,7 +1998,8 @@ final class BrowserReturnKeyDownRoutingTests: XCTestCase {
         XCTAssertTrue(
             shouldDispatchBrowserReturnViaFirstResponderKeyDown(
                 keyCode: 76,
-                firstResponderIsBrowser: true
+                firstResponderIsBrowser: true,
+                flags: []
             )
         )
     }
@@ -2006,7 +2008,8 @@ final class BrowserReturnKeyDownRoutingTests: XCTestCase {
         XCTAssertFalse(
             shouldDispatchBrowserReturnViaFirstResponderKeyDown(
                 keyCode: 13,
-                firstResponderIsBrowser: true
+                firstResponderIsBrowser: true,
+                flags: []
             )
         )
     }
@@ -2015,7 +2018,58 @@ final class BrowserReturnKeyDownRoutingTests: XCTestCase {
         XCTAssertFalse(
             shouldDispatchBrowserReturnViaFirstResponderKeyDown(
                 keyCode: 36,
-                firstResponderIsBrowser: false
+                firstResponderIsBrowser: false,
+                flags: []
+            )
+        )
+    }
+
+    func testRoutesForShiftReturnWhenBrowserFirstResponder() {
+        XCTAssertTrue(
+            shouldDispatchBrowserReturnViaFirstResponderKeyDown(
+                keyCode: 36,
+                firstResponderIsBrowser: true,
+                flags: [.shift]
+            )
+        )
+    }
+
+    func testDoesNotRouteForCommandShiftReturnWhenBrowserFirstResponder() {
+        XCTAssertFalse(
+            shouldDispatchBrowserReturnViaFirstResponderKeyDown(
+                keyCode: 36,
+                firstResponderIsBrowser: true,
+                flags: [.command, .shift]
+            )
+        )
+    }
+
+    func testDoesNotRouteForCommandReturnWhenBrowserFirstResponder() {
+        XCTAssertFalse(
+            shouldDispatchBrowserReturnViaFirstResponderKeyDown(
+                keyCode: 36,
+                firstResponderIsBrowser: true,
+                flags: [.command]
+            )
+        )
+    }
+
+    func testDoesNotRouteForOptionReturnWhenBrowserFirstResponder() {
+        XCTAssertFalse(
+            shouldDispatchBrowserReturnViaFirstResponderKeyDown(
+                keyCode: 36,
+                firstResponderIsBrowser: true,
+                flags: [.option]
+            )
+        )
+    }
+
+    func testDoesNotRouteForControlReturnWhenBrowserFirstResponder() {
+        XCTAssertFalse(
+            shouldDispatchBrowserReturnViaFirstResponderKeyDown(
+                keyCode: 36,
+                firstResponderIsBrowser: true,
+                flags: [.control]
             )
         )
     }