diff -r 4cb1f10316ca -r aedf9e836670 runtime/doc/change.txt
--- a/runtime/doc/change.txt	Thu Oct 11 04:44:33 2012 +0200
+++ b/runtime/doc/change.txt	Tue Oct 16 01:28:47 2012 -0700
@@ -1121,7 +1121,9 @@ 4. Named registers "a to "z or "A to "Z	
 Vim fills these registers only when you say so.  Specify them as lowercase
 letters to replace their previous contents or as uppercase letters to append
 to their previous contents.  When the '>' flag is present in 'cpoptions' then
-a line break is inserted before the appended text.
+a line break is inserted before the appended text.  To disable appending
+altogether, set 'noregisterappend' to have uppercase letters behave the same
+as lowercase.
 
 5. Read-only registers ":, "., "% and "#
 These are '%', '#', ':' and '.'.  You can use them only with the "p", "P",
diff -r 4cb1f10316ca -r aedf9e836670 runtime/doc/options.txt
--- a/runtime/doc/options.txt	Thu Oct 11 04:44:33 2012 +0200
+++ b/runtime/doc/options.txt	Tue Oct 16 01:28:47 2012 -0700
@@ -5492,6 +5492,14 @@ A jump table for the options with a shor
 	matches will be highlighted.  This is used to avoid that Vim hangs
 	when using a very complicated pattern.
 
+						*'registerappend'*
+'registerappend'        boolean (default on)
+			global
+	When set, using a named register with an uppercase letter will append
+	to their previous contents.  Turning off this option could be useful
+	in case you frequently type an uppercase letter on accident when
+	filling a named register.
+
 		*'relativenumber'* *'rnu'* *'norelativenumber'* *'nornu'*
 'relativenumber' 'rnu'	boolean	(default off)
 			local to window
diff -r 4cb1f10316ca -r aedf9e836670 runtime/doc/quickref.txt
--- a/runtime/doc/quickref.txt	Thu Oct 11 04:44:33 2012 +0200
+++ b/runtime/doc/quickref.txt	Tue Oct 16 01:28:47 2012 -0700
@@ -823,6 +823,7 @@ Short explanation of each option:		*opti
 'quoteescape'	  'qe'	    escape characters used in a string
 'readonly'	  'ro'	    disallow writing the buffer
 'redrawtime'	  'rdt'     timeout for 'hlsearch' and |:match| highlighting
+'registerappend' 	    allow append to register with uppercase letter
 'relativenumber'  'rnu'	    show relative line number in front of each line
 'remap'			    allow mappings to work recursively
 'report'		    threshold for reporting nr. of lines changed
diff -r 4cb1f10316ca -r aedf9e836670 src/ops.c
--- a/src/ops.c	Thu Oct 11 04:44:33 2012 +0200
+++ b/src/ops.c	Tue Oct 16 01:28:47 2012 -0700
@@ -894,7 +894,8 @@ get_yank_register(regname, writing)
     else if (ASCII_ISUPPER(i))
     {
 	i = CharOrdUp(i) + 10;
-	y_append = TRUE;
+	if(p_regappend)
+	    y_append = TRUE;
     }
     else if (regname == '-')
 	i = DELETION_REGISTER;
diff -r 4cb1f10316ca -r aedf9e836670 src/option.c
--- a/src/option.c	Thu Oct 11 04:44:33 2012 +0200
+++ b/src/option.c	Tue Oct 16 01:28:47 2012 -0700
@@ -2068,6 +2068,9 @@ static struct vimoption
 			    (char_u *)NULL, PV_NONE,
 #endif
 			    {(char_u *)2000L, (char_u *)0L} SCRIPTID_INIT},
+    {"registerappend", NULL,  P_BOOL,
+			    (char_u *)&p_regappend, PV_NONE,
+			    {(char_u *)TRUE, (char_u *)TRUE} SCRIPTID_INIT}, 
     {"relativenumber", "rnu", P_BOOL|P_VI_DEF|P_RWIN,
 			    (char_u *)VAR_WIN, PV_RNU,
 			    {(char_u *)FALSE, (char_u *)0L} SCRIPTID_INIT},
diff -r 4cb1f10316ca -r aedf9e836670 src/option.h
--- a/src/option.h	Thu Oct 11 04:44:33 2012 +0200
+++ b/src/option.h	Tue Oct 16 01:28:47 2012 -0700
@@ -495,6 +495,7 @@ EXTERN char_u	*p_popt;	/* 'printoptions'
 EXTERN char_u	*p_header;	/* 'printheader' */
 #endif
 EXTERN int	p_prompt;	/* 'prompt' */
+EXTERN int	p_regappend;	/* 'registerappend' */
 #ifdef FEAT_GUI
 EXTERN char_u	*p_guifont;	/* 'guifont' */
 # ifdef FEAT_XFONTSET