diff --git a/binaries/data/config/system.cfg b/binaries/data/config/system.cfg
index 3d47d787ba..a79e196844 100755
--- a/binaries/data/config/system.cfg
+++ b/binaries/data/config/system.cfg
@@ -9,6 +9,13 @@ vsync=false
 
 ; Hotkey mappings:
 
+; Each one of the specified keys will trigger the action on the left
+; for multiple-key combinations, separate keys with '+' and enclose the entire thing
+;   in doublequotes.
+
+; The keys you can use are in source/lib/KeyNames.cpp. I realise this isn't particularly
+; useful for people without access to said file.
+
 hotkey.exit = F12, Escape
 hotkey.screenshot = PrtSc
 hotkey.wireframe = W
@@ -32,8 +39,7 @@ hotkey.selection.group.snap = LeftAlt, RightAlt
 hotkey.selection.snap = Home
 hotkey.contextorder.next = CloseBracket
 hotkey.contextorder.previous = OpenBracket
-hotkey.highlightall = o
-
+hotkey.highlightall = O