diff --git a/help/CommandLine.html b/help/CommandLine.html
index 0084ba2e..9abd4f0c 100644
--- a/help/CommandLine.html
+++ b/help/CommandLine.html
@@ -82,6 +82,9 @@
best: picks the highest resolution where the height is an integer multiple of (192*2)
nnnn: select a specific resolution with height=nnnn pixels
+ -fs-width=<nnnn>
+ Use in conjunction with -fs-height to select a better aspect ratio for full-screen mode.
+ EG. for 4:3 aspect ratio on monitors that support it: -no-full-screen -fs-width=1600 -fs-height=1200
NB. Combine with -no-full-screen to start in Windowed mode. Without this it'll just default to full-screen.
NB. When switching to Windowed mode the default desktop resolution will be restored, and when switching back to full-screen mode this better resolution will again be used.
-rom <file>