diff --git a/src/viewport.cpp b/src/viewport.cpp
index 63cde4ba32..447d1ced16 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -555,13 +555,26 @@ static void DoSetViewportPosition(Window *w, const int left, const int top, cons
 
 	if (_networking) NetworkUndrawChatMessage();
 
-	std::sort(_vp_redraw_regions.begin(), _vp_redraw_regions.end(), [&](const ViewportRedrawRegion &a, const ViewportRedrawRegion &b) {
-		if (a.coords.right <= b.coords.left && xo > 0) return true;
-		if (a.coords.left >= b.coords.right && xo < 0) return true;
-		if (a.coords.bottom <= b.coords.top && yo > 0) return true;
-		if (a.coords.top >= b.coords.bottom && yo < 0) return true;
-		return false;
-	});
+	if (xo != 0) {
+		std::sort(_vp_redraw_regions.begin(), _vp_redraw_regions.end(), [&](const ViewportRedrawRegion &a, const ViewportRedrawRegion &b) {
+			if (a.coords.right <= b.coords.left && xo > 0) return true;
+			if (a.coords.left >= b.coords.right && xo < 0) return true;
+			return false;
+		});
+		if (yo != 0) {
+			std::stable_sort(_vp_redraw_regions.begin(), _vp_redraw_regions.end(), [&](const ViewportRedrawRegion &a, const ViewportRedrawRegion &b) {
+				if (a.coords.bottom <= b.coords.top && yo > 0) return true;
+				if (a.coords.top >= b.coords.bottom && yo < 0) return true;
+				return false;
+			});
+		}
+	} else {
+		std::sort(_vp_redraw_regions.begin(), _vp_redraw_regions.end(), [&](const ViewportRedrawRegion &a, const ViewportRedrawRegion &b) {
+			if (a.coords.bottom <= b.coords.top && yo > 0) return true;
+			if (a.coords.top >= b.coords.bottom && yo < 0) return true;
+			return false;
+		});
+	}
 
 	while (!_vp_redraw_regions.empty()) {
 		const Rect &rect = _vp_redraw_regions.back().coords;