diff --git a/shell.asm b/shell.asm
index ccab412..5c42648 100644
--- a/shell.asm
+++ b/shell.asm
@@ -228,23 +228,25 @@ mouse:
 
 	cmp byte [si + window.status], WINDOW_MOVE
 	jne .not_move
-	call move
+		call move
 	.not_move:
 	cmp byte [si + window.status], WINDOW_RESIZE
 	jne .not_resize
-	call resize
+		call resize
 	.not_resize:
 
-	sub cx, [si + window.x]
-	jc .outside
-	cmp [si + window.width], cx
-	jle .outside
-	add cx, [si + window.x]
-	sub bx, [si + window.y]
-	jc .outside
-	cmp [si + window.height], bx
-	jle .outside
-	add bx, [si + window.y]
+	cmp cx, [si + window.x]
+	jl .outside ; x < window_x
+	cmp bx, [si + window.y]
+	jl .outside ; y < window_y
+	mov bp, [si + window.x]
+	add bp, [si + window.width]
+	cmp bp, cx
+	jle .outside ; window_x + window_width <= x
+	mov bp, [si + window.y]
+	add bp, [si + window.height]
+	cmp bp, bx
+	jle .outside ; window_y + window_height <= y
 
 	cmp byte [si + window.mouse_released_inside], 0
 	je .not_clicking