diff --git a/src/p_scroll.cpp b/src/p_scroll.cpp
index d0a8f4769f..52be13d56d 100644
--- a/src/p_scroll.cpp
+++ b/src/p_scroll.cpp
@@ -345,16 +345,12 @@ DScroller::DScroller (double dx, double dy, const line_t *l,
 					 int control, int accel, EScrollPos scrollpos)
 	: DThinker (STAT_SCROLLER)
 {
-	if (tagManager.GetFirstLineID(l) == 300)
-	{
-		int a = 0;
-	}
 	double x = fabs(l->Delta().X), y = fabs(l->Delta().Y), d;
 	if (y > x) d = x, x = y, y = d;
 
 	d = x / g_sin(g_atan2(y, x) + M_PI / 2);
-	x = (-dy * l->Delta().Y + dx * l->Delta().X) / d;
-	y = (-dx * l->Delta().Y - dy * l->Delta().X) / d;
+	x = -(dy * l->Delta().Y + dx * l->Delta().X) / d;
+	y = -(dx * l->Delta().Y - dy * l->Delta().X) / d;
 
 	m_Type = EScroll::sc_side;
 	m_dx = x;