SDL: Revert "x11: Filter out duplicate key presses when an IME is active"

From 3304d24bea47d0de9a7f841fde517695ad4d6e6f Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Mon, 12 May 2025 19:16:23 -0400
Subject: [PATCH] Revert "x11: Filter out duplicate key presses when an IME is
 active"

This reverts commit f4813ca2cf9953f60ec406ab63e07bd68f56c4ee.
---
 src/video/x11/SDL_x11events.c | 8 ++------
 src/video/x11/SDL_x11video.h  | 2 --
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/video/x11/SDL_x11events.c b/src/video/x11/SDL_x11events.c
index 364e05a77988f..a4e5d9caf67a3 100644
--- a/src/video/x11/SDL_x11events.c
+++ b/src/video/x11/SDL_x11events.c
@@ -988,11 +988,8 @@ void X11_HandleKeyEvent(SDL_VideoDevice *_this, SDL_WindowData *windowdata, SDL_
     }
 
     if (pressed) {
-        // Duplicate events may be sent when an IME is active; don't send multiple keydown events for the same serial.
-        if (videodata->last_key_down_serial != xevent->xkey.serial) {
-            X11_HandleModifierKeys(videodata, scancode, true, true);
-            SDL_SendKeyboardKeyIgnoreModifiers(timestamp, keyboardID, keycode, scancode, true);
-        }
+        X11_HandleModifierKeys(videodata, scancode, true, true);
+        SDL_SendKeyboardKeyIgnoreModifiers(timestamp, keyboardID, keycode, scancode, true);
 
         // Synthesize a text event if the IME didn't consume a printable character
         if (*text && !(SDL_GetModState() & (SDL_KMOD_CTRL | SDL_KMOD_ALT))) {
@@ -1002,7 +999,6 @@ void X11_HandleKeyEvent(SDL_VideoDevice *_this, SDL_WindowData *windowdata, SDL_
         }
 
         X11_UpdateUserTime(windowdata, xevent->xkey.time);
-        videodata->last_key_down_serial = xevent->xkey.serial;
     } else {
         if (X11_KeyRepeat(display, xevent)) {
             // We're about to get a repeated key down, ignore the key up
diff --git a/src/video/x11/SDL_x11video.h b/src/video/x11/SDL_x11video.h
index d5a9299b4eea1..a336a800f598f 100644
--- a/src/video/x11/SDL_x11video.h
+++ b/src/video/x11/SDL_x11video.h
@@ -140,8 +140,6 @@ struct SDL_VideoData
     int xinput_master_pointer_device;
     bool xinput_hierarchy_changed;
 
-    unsigned long last_key_down_serial;
-
     int xrandr_event_base;
     struct
     {