updated for version 7.0210
diff --git a/runtime/doc/undo.txt b/runtime/doc/undo.txt
index 433fc75..bdb7ffb 100644
--- a/runtime/doc/undo.txt
+++ b/runtime/doc/undo.txt
@@ -1,4 +1,4 @@
-*undo.txt* For Vim version 7.0aa. Last change: 2003 Oct 21
+*undo.txt* For Vim version 7.0aa. Last change: 2006 Feb 28
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -10,7 +10,8 @@
1. Undo and redo commands |undo-commands|
2. Two ways of undo |undo-two-ways|
-3. Remarks about undo |undo-remarks|
+3. Undo blocks |undo-blocks|
+4. Remarks about undo |undo-remarks|
==============================================================================
1. Undo and redo commands *undo-commands*
@@ -72,7 +73,36 @@
words, in Nvi it does nothing.
==============================================================================
-3. Remarks about undo *undo-remarks*
+3. Undo blocks *undo-blocks*
+
+One undo command normally undoes a typed command, no matter how many changes
+that command makes. This sequence of undo-able changes forms an undo block.
+Thus if the typed key(s) call a function, all the commands in the function are
+undone together.
+
+If you want to write a function or script that doesn't create a new undoable
+change but joins in with the previous change use this command:
+
+ *:undoj* *:undojoin*
+:undoj[oin] Join further changes with the previous undo block.
+ Warning: Use with care, it may prevent the user from
+ properly undoing changes.
+ {not in Vi}
+
+This is most useful when you need to prompt the user halfway a change. For
+example in a function that calls |getchar()|. Do make sure that there was a
+related change before this that you must join with.
+
+This doesn't work by itself, because the next key press will start a new
+change again. But you can do something like this: >
+
+ :undojoin | delete
+
+After this an "u" command will undo the delete command and the previous
+change.
+
+==============================================================================
+4. Remarks about undo *undo-remarks*
The number of changes that are remembered is set with the 'undolevels' option.
If it is zero, the Vi-compatible way is always used. If it is negative no