diff --git a/OpenRA.Game/Graphics/Viewport.cs b/OpenRA.Game/Graphics/Viewport.cs
index a28bfbd66f..d59338a8f3 100644
--- a/OpenRA.Game/Graphics/Viewport.cs
+++ b/OpenRA.Game/Graphics/Viewport.cs
@@ -282,11 +282,12 @@ namespace OpenRA.Graphics
 		IEnumerable<MPos> CandidateMouseoverCells(int2 world)
 		{
 			var map = worldRenderer.World.Map;
+			var tileScale = map.Grid.TileScale / 2;
 			var minPos = worldRenderer.ProjectedPosition(world);
 
-			// Find all the cells that could potentially have been clicked
-			var a = map.CellContaining(minPos - new WVec(1024, 0, 0)).ToMPos(map.Grid.Type);
-			var b = map.CellContaining(minPos + new WVec(512, 512 * map.Grid.MaximumTerrainHeight, 0)).ToMPos(map.Grid.Type);
+			// Find all the cells that could potentially have been clicked.
+			var a = map.CellContaining(minPos - new WVec(tileScale, 0, 0)).ToMPos(map.Grid.Type);
+			var b = map.CellContaining(minPos + new WVec(tileScale, tileScale * map.Grid.MaximumTerrainHeight, 0)).ToMPos(map.Grid.Type);
 
 			for (var v = b.V; v >= a.V; v--)
 				for (var u = b.U; u >= a.U; u--)