diff --git a/patches/patchinstall.sh b/patches/patchinstall.sh
index b3e92a4a..d50baea1 100755
--- a/patches/patchinstall.sh
+++ b/patches/patchinstall.sh
@@ -427,6 +427,7 @@ patch_enable_all ()
 	enable_winex11_DefaultDisplayFrequency="$1"
 	enable_winex11_MWM_Decorations="$1"
 	enable_winex11_SC_KEYMENU="$1"
+	enable_winex11_UpdateLayeredWindow="$1"
 	enable_winex11_WM_WINDOWPOSCHANGING="$1"
 	enable_winex11_Window_Groups="$1"
 	enable_winex11_Window_Style="$1"
@@ -1499,6 +1500,9 @@ patch_enable ()
 		winex11-SC_KEYMENU)
 			enable_winex11_SC_KEYMENU="$2"
 			;;
+		winex11-UpdateLayeredWindow)
+			enable_winex11_UpdateLayeredWindow="$2"
+			;;
 		winex11-WM_WINDOWPOSCHANGING)
 			enable_winex11_WM_WINDOWPOSCHANGING="$2"
 			;;
@@ -8812,6 +8816,21 @@ if test "$enable_winex11_SC_KEYMENU" -eq 1; then
 	) >> "$patchlist"
 fi
 
+# Patchset winex11-UpdateLayeredWindow
+# |
+# | This patchset fixes the following Wine bugs:
+# |   *	[#33943] Fix alpha blending in X11DRV_UpdateLayeredWindow
+# |
+# | Modified files:
+# |   *	dlls/winex11.drv/window.c
+# |
+if test "$enable_winex11_UpdateLayeredWindow" -eq 1; then
+	patch_apply winex11-UpdateLayeredWindow/0001-winex11-Fix-alpha-blending-in-X11DRV_UpdateLayeredWi.patch
+	(
+		printf '%s\n' '+    { "Sebastian Lackner", "winex11: Fix alpha blending in X11DRV_UpdateLayeredWindow.", 1 },';
+	) >> "$patchlist"
+fi
+
 # Patchset winex11-_NET_ACTIVE_WINDOW
 # |
 # | This patchset fixes the following Wine bugs:
diff --git a/patches/winex11-UpdateLayeredWindow/0001-winex11-Fix-alpha-blending-in-X11DRV_UpdateLayeredWi.patch b/patches/winex11-UpdateLayeredWindow/0001-winex11-Fix-alpha-blending-in-X11DRV_UpdateLayeredWi.patch
new file mode 100644
index 00000000..4cbb5a1e
--- /dev/null
+++ b/patches/winex11-UpdateLayeredWindow/0001-winex11-Fix-alpha-blending-in-X11DRV_UpdateLayeredWi.patch
@@ -0,0 +1,111 @@
+From 73bf4a03497e732b42fff4e5d0d63c442fd70bc0 Mon Sep 17 00:00:00 2001
+From: Sebastian Lackner <sebastian@fds-team.de>
+Date: Tue, 24 Jan 2017 12:37:46 +0100
+Subject: winex11: Fix alpha blending in X11DRV_UpdateLayeredWindow.
+
+Based on a patch by Dmitry Timoshkov.
+---
+ dlls/winex11.drv/window.c | 36 +++++++++++++++++-------------------
+ 1 file changed, 17 insertions(+), 19 deletions(-)
+
+diff --git a/dlls/winex11.drv/window.c b/dlls/winex11.drv/window.c
+index 7408a0eb480..3f169ea296f 100644
+--- a/dlls/winex11.drv/window.c
++++ b/dlls/winex11.drv/window.c
+@@ -410,14 +410,11 @@ static void sync_window_region( struct x11drv_win_data *data, HRGN win_region )
+ 
+ 
+ /***********************************************************************
+- *              sync_window_opacity
++ *              set_window_opacity
+  */
+-static void sync_window_opacity( Display *display, Window win,
+-                                 COLORREF key, BYTE alpha, DWORD flags )
++static void set_window_opacity( Display *display, Window win, BYTE alpha )
+ {
+-    unsigned long opacity = 0xffffffff;
+-
+-    if (flags & LWA_ALPHA) opacity = (0xffffffff / 0xff) * alpha;
++    unsigned long opacity = (0xffffffff / 0xff) * alpha;
+ 
+     if (opacity == 0xffffffff)
+         XDeleteProperty( display, win, x11drv_atom(_NET_WM_WINDOW_OPACITY) );
+@@ -1527,7 +1524,7 @@ static void create_whole_window( struct x11drv_win_data *data )
+ 
+     /* set the window opacity */
+     if (!GetLayeredWindowAttributes( data->hwnd, &key, &alpha, &layered_flags )) layered_flags = 0;
+-    sync_window_opacity( data->display, data->whole_window, key, alpha, layered_flags );
++    set_window_opacity( data->display, data->whole_window, (layered_flags & LWA_ALPHA) ? alpha : 0xff );
+ 
+     XFlush( data->display );  /* make sure the window exists before we start painting to it */
+ 
+@@ -1647,7 +1644,7 @@ void CDECL X11DRV_SetWindowStyle( HWND hwnd, INT offset, STYLESTRUCT *style )
+     {
+         data->layered = FALSE;
+         set_window_visual( data, &default_visual );
+-        sync_window_opacity( data->display, data->whole_window, 0, 0, 0 );
++        set_window_opacity( data->display, data->whole_window, 0xff );
+         if (data->surface) set_surface_color_key( data->surface, CLR_INVALID );
+     }
+ done:
+@@ -2536,7 +2533,7 @@ void CDECL X11DRV_SetLayeredWindowAttributes( HWND hwnd, COLORREF key, BYTE alph
+     if (data)
+     {
+         if (data->whole_window)
+-            sync_window_opacity( data->display, data->whole_window, key, alpha, flags );
++            set_window_opacity( data->display, data->whole_window, (flags & LWA_ALPHA) ? alpha : 0xff );
+         if (data->surface)
+             set_surface_color_key( data->surface, (flags & LWA_COLORKEY) ? key : CLR_INVALID );
+ 
+@@ -2560,7 +2557,7 @@ void CDECL X11DRV_SetLayeredWindowAttributes( HWND hwnd, COLORREF key, BYTE alph
+         Window win = X11DRV_get_whole_window( hwnd );
+         if (win)
+         {
+-            sync_window_opacity( gdi_display, win, key, alpha, flags );
++            set_window_opacity( gdi_display, win, (flags & LWA_ALPHA) ? alpha : 0xff );
+             if (flags & LWA_COLORKEY)
+                 FIXME( "LWA_COLORKEY not supported on foreign process window %p\n", hwnd );
+         }
+@@ -2576,7 +2573,6 @@ BOOL CDECL X11DRV_UpdateLayeredWindow( HWND hwnd, const UPDATELAYEREDWINDOWINFO
+ {
+     struct window_surface *surface;
+     struct x11drv_win_data *data;
+-    BLENDFUNCTION blend = { AC_SRC_OVER, 0, 255, 0 };
+     COLORREF color_key = (info->dwFlags & ULW_COLORKEY) ? info->crKey : CLR_INVALID;
+     char buffer[FIELD_OFFSET( BITMAPINFO, bmiColors[256] )];
+     BITMAPINFO *bmi = (BITMAPINFO *)buffer;
+@@ -2604,6 +2600,10 @@ BOOL CDECL X11DRV_UpdateLayeredWindow( HWND hwnd, const UPDATELAYEREDWINDOWINFO
+     }
+     else set_surface_color_key( surface, color_key );
+ 
++    if (data->whole_window)
++        set_window_opacity( data->display, data->whole_window,
++                            (info->dwFlags & ULW_ALPHA) ? info->pblend->SourceConstantAlpha : 0xff );
++
+     if (surface) window_surface_add_ref( surface );
+     release_win_data( data );
+ 
+@@ -2627,14 +2627,12 @@ BOOL CDECL X11DRV_UpdateLayeredWindow( HWND hwnd, const UPDATELAYEREDWINDOWINFO
+     {
+         IntersectRect( &rect, &rect, info->prcDirty );
+         memcpy( src_bits, dst_bits, bmi->bmiHeader.biSizeImage );
+-        PatBlt( hdc, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, BLACKNESS );
+-    }
+-    ret = GdiAlphaBlend( hdc, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,
+-                         info->hdcSrc,
+-                         rect.left + (info->pptSrc ? info->pptSrc->x : 0),
+-                         rect.top + (info->pptSrc ? info->pptSrc->y : 0),
+-                         rect.right - rect.left, rect.bottom - rect.top,
+-                         (info->dwFlags & ULW_ALPHA) ? *info->pblend : blend );
++    }
++    ret = BitBlt( hdc, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,
++                  info->hdcSrc,
++                  rect.left + (info->pptSrc ? info->pptSrc->x : 0),
++                  rect.top + (info->pptSrc ? info->pptSrc->y : 0),
++                  SRCCOPY );
+     if (ret)
+     {
+         memcpy( dst_bits, src_bits, bmi->bmiHeader.biSizeImage );
+-- 
+2.11.0
+
diff --git a/patches/winex11-UpdateLayeredWindow/definition b/patches/winex11-UpdateLayeredWindow/definition
new file mode 100644
index 00000000..fc7874a5
--- /dev/null
+++ b/patches/winex11-UpdateLayeredWindow/definition
@@ -0,0 +1 @@
+Fixes: [33943] Fix alpha blending in X11DRV_UpdateLayeredWindow