[JW Lua] Undo after opening another file

[Jan Angermüller]

Jari,

after opening a new file, editing a bit, saving, then opening another 
file and editing a bit,
then pressing several times CTRL-Z, I can undo the "open" and get back 
to the old file.
I can then even switch back to the new file with CTRL-Y.
Hm, I don't know if undo should go beyond opening a new file. I wouldn't 
do that,
but that's your decision.

But: I am not sure if all settings are still ok, after going back or 
forth to the other file.
For example, the file name right below the New, Open, etc. buttons does 
not change
to the file name of the first file, when going back to the first file, 
but sticks with the
second file name.
So when going back to the first file, it may save with the file name of 
the second file.
(well, I didn't try that, but at least when selecting "Save as", the 
file name from the
second file is used, although I am on the code from the first file).
Maybe you can have a look at that ?

Jan