diff --git a/vimfiles.stefan/doc/tags b/vimfiles.stefan/doc/tags
index 5144864..a0b94ef 100644
--- a/vimfiles.stefan/doc/tags
+++ b/vimfiles.stefan/doc/tags
@@ -60,8 +60,10 @@ DelAllMultipleEmptyLines	vimsuite.txt	/*DelAllMultipleEmptyLines*
 DelAllMultipleSameLines	vimsuite.txt	/*DelAllMultipleSameLines*
 DelAllTrailingWhitespace	vimsuite.txt	/*DelAllTrailingWhitespace*
 DirDiff	vimsuite.txt	/*DirDiff*
+GVimMerge	vimsuite.txt	/*GVimMerge*
 GrepDir	vimsuite.txt	/*GrepDir*
 GrepFiles	vimsuite.txt	/*GrepFiles*
+Merge	vimsuite.txt	/*Merge*
 Project	vimsuite.txt	/*Project*
 Projekt	vimsuite.txt	/*Projekt*
 Reformat	vimsuite.txt	/*Reformat*
diff --git a/vimfiles.stefan/doc/vimsuite.txt b/vimfiles.stefan/doc/vimsuite.txt
index bfae5f6..af23025 100644
--- a/vimfiles.stefan/doc/vimsuite.txt
+++ b/vimfiles.stefan/doc/vimsuite.txt
@@ -179,6 +179,14 @@ Alle Zeilen, die l
                                                               *:InsertCHeader*
 :InsertCHeader   Fügt das Template ... ein
 
+                                                           *GVimMerge* *Merge*
+gvimmerge                               Tool zur Unterstützung beim mergen
+
+Um GVim als Tool zum Mergen für eine Versionsverwaltung zu verwenden kann 
+dieser dort als Merge-Tool eingetragen werden. Der Eintrag sollte 
+folgendermaßen ausshen:
+.../vimsuite/vimfiles.stefan/tools/gvimmerge.bat <base> <mine> <theirs> <merged>
+
 ==============================================================================
                                                                *cscope_macros*
 
diff --git a/vimfiles.stefan/tools/gvimmerge.bat b/vimfiles.stefan/tools/gvimmerge.bat
new file mode 100644
index 0000000..fe439e6
--- /dev/null
+++ b/vimfiles.stefan/tools/gvimmerge.bat
@@ -0,0 +1,17 @@
+@echo off
+setlocal
+set vimdir=%~dp0..\..\..
+set vimprg=%vimdir%\vim74\gvim.exe
+set vimscript=%~dp0gvimmerge.vim
+set base=%1
+set mine=%2
+set theirs=%3
+set merged=%4
+
+if not exist %vimprg% (
+  echo gvim.exe nicht gefunden
+)
+
+set cmd=%vimprg% -f -R %base% %mine% %theirs% %merged% -S %vimscript%
+echo %cmd%
+%cmd%
diff --git a/vimfiles.stefan/tools/gvimmerge.vim b/vimfiles.stefan/tools/gvimmerge.vim
new file mode 100644
index 0000000..40d45c1
--- /dev/null
+++ b/vimfiles.stefan/tools/gvimmerge.vim
@@ -0,0 +1,31 @@
+function s:OpenDiffTab(left, right)
+    tabnew
+    execute 'buffer' a:left
+    diffthis
+    execute 'rightbelow vertical sbuffer' a:right
+    diffthis
+endfunction
+
+function s:FixLineendings()
+    if !exists('b:reload_dos') && !&binary && &ff=='unix' && (0 < search('\r$', 'nc'))
+        edit ++ff=dos
+        echom 'fixed lineendings'
+        let b:reload_dos = 1
+    endif
+endfunction
+
+function s:OpenMergeTabs()
+    set columns=200
+    call s:OpenDiffTab(1, 4)
+    call s:FixLineendings()
+    setlocal noreadonly modifiable
+    call s:OpenDiffTab(2, 4)
+    call s:OpenDiffTab(3, 4)
+    call s:OpenDiffTab(1, 2)
+    call s:OpenDiffTab(1, 3)
+    call s:OpenDiffTab(2, 3)
+    tabfirst
+    tabclose
+endfunction
+
+call s:OpenMergeTabs()
diff --git a/vimfiles.stefan/vimrc b/vimfiles.stefan/vimrc
index 3fe7105..6be20da 100644
--- a/vimfiles.stefan/vimrc
+++ b/vimfiles.stefan/vimrc
@@ -156,7 +156,11 @@ nnoremap gb :call GotoLastFile()<CR>
 " -----------
 set sessionoptions=blank,buffers,curdir,folds,help,resize,tabpages,winsize
 " open window size
-autocmd GUIEnter * winsize 100 60
+if &diff
+    autocmd GUIEnter * set lines=60 columns=200
+else
+    autocmd GUIEnter * set lines=60 columns=100
+endif
 " read and write files automatically
 set autoread
 set autowrite