diff --git a/data/gui/default/window/campaign_difficulty.cfg b/data/gui/default/window/campaign_difficulty.cfg
index 949945c88bd..19b65e097a9 100644
--- a/data/gui/default/window/campaign_difficulty.cfg
+++ b/data/gui/default/window/campaign_difficulty.cfg
@@ -15,6 +15,8 @@
 		vertical_placement = "center"
 		horizontal_placement = "center"
 
+		maximum_width = 800
+
 		[linked_group]
 			id = "icon"
 			fixed_width = "true"