Update runtime files.
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 4a47c33..6606524 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt* For Vim version 8.0. Last change: 2017 Feb 06
+*syntax.txt* For Vim version 8.0. Last change: 2017 Jun 04
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -4812,10 +4812,11 @@
Example: >
:highlight Normal ctermfg=grey ctermbg=darkblue
< When setting the "ctermbg" color for the Normal group, the
- 'background' option will be adjusted automatically. This causes the
- highlight groups that depend on 'background' to change! This means
- you should set the colors for Normal first, before setting other
- colors.
+ 'background' option will be adjusted automatically, under the
+ condition that the color is recognized and 'background' was not set
+ explicitly. This causes the highlight groups that depend on
+ 'background' to change! This means you should set the colors for
+ Normal first, before setting other colors.
When a colorscheme is being used, changing 'background' causes it to
be reloaded, which may reset all colors (including Normal). First
delete the "g:colors_name" variable when you don't want this.