--- a/Themes.wiki	Thu Mar 22 15:58:53 2018 +0000
+++ b/Themes.wiki	Thu Mar 22 16:00:00 2018 +0000
@@ -9,7 +9,7 @@
 === Theme types ===
 *Full themes* are themes which can be used together with random maps. Those usually appear in the multiplayer screen for selection as well. Most themes are full themes and when talking about themes without qualification, full themes are meant.
 
-*Background themes* are minimal themes without this capability. They lack land textures, thus they can only be used as a background (hence the name). Background themes work only together with image maps or forts. Examples for background themes in Hedgewars are Planes and Blox, the default themes of the image maps of the same name.
+*Background themes* are minimal themes without this capability. They lack land textures, thus they can only be used as a background (hence the name). Background themes work only together with image maps or forts. Examples for background themes in Hedgewars are Planes and Blox, the default themes of the image maps of the same name. Background themes *must* be hidden.
 
 === Theme structure ===
 Technically, a theme consists of a configuration file and many media files (PNG images). Themes can define many images, or just a very few. You can set flakes, clouds, water color, the background, land texture and much, much more. Many files and settings are optional and have (more or less) sane defaults.