From 1cb50d769eebb752c374e5f4ace5c003f7181ab6 Mon Sep 17 00:00:00 2001
From: KoppePan <7379133+0141KoppePan@users.noreply.github.com>
Date: Wed, 10 Dec 2025 22:21:15 +0900
Subject: [PATCH 1/2] fix: Handle Microsoft IME issue with Shift key detection

---
 ui/src/components/WebRTCVideo.tsx | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ui/src/components/WebRTCVideo.tsx b/ui/src/components/WebRTCVideo.tsx
index c7a9d45c0..c0431a473 100644
--- a/ui/src/components/WebRTCVideo.tsx
+++ b/ui/src/components/WebRTCVideo.tsx
@@ -260,6 +260,9 @@ export default function WebRTCVideo({ hasConnectionIssues }: { hasConnectionIssu
         code = "Henkan";
     } else if (code === "NonConvert") {
         code = "Muhenkan";
+    // Microsoft IME fix
+    } else if (key === "Shift" && code === "") {
+        code = "ShiftRight"
     }
 
     return code;

From 2b0dc2c67a69c8c5ffec46b429a04a8e052aac5e Mon Sep 17 00:00:00 2001
From: KoppePan <7379133+0141KoppePan@users.noreply.github.com>
Date: Wed, 10 Dec 2025 22:53:39 +0900
Subject: [PATCH 2/2] fix: Microsoft IME keydown handling for Zenkaku/Hankaku
 keys

---
 ui/src/components/WebRTCVideo.tsx | 37 ++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/ui/src/components/WebRTCVideo.tsx b/ui/src/components/WebRTCVideo.tsx
index c0431a473..65eae72e7 100644
--- a/ui/src/components/WebRTCVideo.tsx
+++ b/ui/src/components/WebRTCVideo.tsx
@@ -306,6 +306,13 @@ export default function WebRTCVideo({ hasConnectionIssues }: { hasConnectionIssu
           altGrLoopRef.current = true;
           lastKeyDownRef.current = null;
         }
+
+        // Microsoft IME fix:
+        // Effective keydown events are consumed by IME (reported as "Process"),
+        // so we handle the full press/release cycle in the keyup handler instead.
+        if (["Zenkaku", "Hankaku", "ZenkakuHankaku"].includes(e.key)) {
+          return;
+        }
       }
 
       // When pressing the meta key + another key, the key will never trigger a keyup
@@ -345,21 +352,29 @@ export default function WebRTCVideo({ hasConnectionIssues }: { hasConnectionIssu
         return;
       }
 
-      // On Windows, handle ControlLeft specially to preserve FIFO semantics with AltGr buffering.
-      if (isWindowsClient && hidKey === keys.ControlLeft) {
+      if (isWindowsClient) {
+        // On Windows, handle ControlLeft specially to preserve FIFO semantics with AltGr buffering.
+        if (hidKey === keys.ControlLeft) {
+          // Synthetic AltGr ControlLeft: never sent a down, swallow the release as well.
+          if (altGrLoopRef.current) {
+            altGrLoopRef.current = false;
+            return;
+          }
 
-        // Synthetic AltGr ControlLeft: never sent a down, swallow the release as well.
-        if (altGrLoopRef.current) {
-          altGrLoopRef.current = false;
-          return;
-        }
+          // Very fast real Ctrl tap: flush the pending down before the up.
+          if (lastKeyDownRef.current?.hidKey === keys.ControlLeft) {
+            handleKeyPress(keys.ControlLeft, true);
+          }
 
-        // Very fast real Ctrl tap: flush the pending down before the up.
-        if (lastKeyDownRef.current?.hidKey === keys.ControlLeft) {
-          handleKeyPress(keys.ControlLeft, true);
+          lastKeyDownRef.current = null;
         }
 
-        lastKeyDownRef.current = null;
+        // Microsoft IME fix:
+        // Synthesize the missing keydown event to ensure a complete key press cycle.
+        if (["Zenkaku", "Hankaku", "ZenkakuHankaku"].includes(e.key)) {
+          console.debug(`Synthesizing missed key down for IME key: ${e.key}`);
+          handleKeyPress(hidKey, true);
+        }
       }
 
       console.debug(`Key up: ${hidKey}`);