Index: binaries/data/mods/public/gui/session/input.js
===================================================================
--- binaries/data/mods/public/gui/session/input.js
+++ binaries/data/mods/public/gui/session/input.js
@@ -1338,9 +1338,13 @@
 function OnTrainMouseWheel(dir)
 {
 	if (Engine.HotkeyIsPressed("session.batchtrain"))
+	{
 		g_BatchSize += dir / Engine.ConfigDB_GetValue("user", "gui.session.scrollbatchratio");
-	if (g_BatchSize < 1 || !Number.isFinite(g_BatchSize))
-		g_BatchSize = 1;
+
+		if (g_BatchSize < 1 || !Number.isFinite(g_BatchSize))
+			g_BatchSize = 1;
+		updateSelectionDetails();
+	}
 }
 
 function getBuildingsWhichCanTrainEntity(entitiesToCheck, trainEntType)