diff --git a/ponydos.asm b/ponydos.asm
index cf91f31..b3c6bb5 100644
--- a/ponydos.asm
+++ b/ponydos.asm
@@ -66,8 +66,7 @@ load_shell:
 	call 0:modify_sectors
 	; TODO: error management? Surely this works...
 
-	xor ax, ax ; WM_INITIALIZE
-	call 0x1000:0
+	call 0x1000:3
 
 initialize_screen:
 	; Disable text cursor
@@ -100,7 +99,7 @@ mainloop:
 		push ax ; Call segment
 		;push word 0 ; Call offset
 		push cs ; Call offset
-		mov ax, WM_PAINT
+		xor ax, ax ; WM_PAINT
 		retf
 	.draw_end:
 
diff --git a/ponydos_static.inc b/ponydos_static.inc
index 95345e7..034c970 100644
--- a/ponydos_static.inc
+++ b/ponydos_static.inc
@@ -6,5 +6,4 @@ GLOBAL_DIRENTS equ 0x2000
 FS_DIRENT_SIZE equ 32
 FS_FILE_MAX_SIZE equ 128
 
-WM_INITIALIZE equ 0
-WM_PAINT equ 1
+WM_PAINT equ 0
diff --git a/shell.asm b/shell.asm
index 9909260..217f98e 100644
--- a/shell.asm
+++ b/shell.asm
@@ -5,43 +5,16 @@ bits 16
 
 org 0
 
-process_event:
-	push ax
-	push bx
-	push cx
-	push dx
-	push si
-	push di
-	push bp
-	push ds
-	push es
-
-	mov bp, cs
-	mov ds, bp
-	mov es, bp
-
-	cmp ax, WM_INITIALIZE
-	jne .not_initialize
-	call initialize
-	.not_initialize:
-
-	cmp ax, WM_PAINT
-	jne .not_paint
-	call paint
-	.not_paint:
-
-	pop es
-	pop ds
-	pop bp
-	pop di
-	pop si
-	pop dx
-	pop cx
-	pop bx
-	pop ax
-	retf
+; 0x0000
+jmp near process_event
 
+; 0x0003
 initialize:
+	push ds
+
+	push cs
+	pop ds
+
 	; Set wallpaper
 	mov si, wallpaper_name
 	xor dx, dx
@@ -81,7 +54,39 @@ initialize:
 	mov dx, 40
 	call print_ls
 
-	ret
+	pop ds
+	retf
+
+process_event:
+	push ax
+	push bx
+	push cx
+	push dx
+	push si
+	push di
+	push bp
+	push ds
+	push es
+
+	mov bp, cs
+	mov ds, bp
+	mov es, bp
+
+	cmp ax, WM_PAINT
+	jne .not_paint
+	call paint
+	.not_paint:
+
+	pop es
+	pop ds
+	pop bp
+	pop di
+	pop si
+	pop dx
+	pop cx
+	pop bx
+	pop ax
+	retf
 
 paint:
 	mov bp, cs