Rated 5 out of 5 stars

OMFG, I thought your extension adds Character Encoding to the top-level menu and that's why I've installed it. Nvm then, your extension works for me. I just expected something else (should have re-read the description more carefully).
EDIT: thanks for that small extension for me - now I'm happy.
> // Remove Charset Button (avaiable through View Menu)
> remove(document.getElementById("appmenu_charsetMenu"));
And why do you _delete_ items in your extension? That is the cause of all the errors.
You'd better add id or class to those elements and hide them using CSS style: .someclass {display:none;}

This review is for a previous version of the add-on (1.0.0.0). 

New Old Menu removes Character Encoding menu item in top level menu (is in view menu on the right side). After disabling New Old Menu, I see it - but it seems to be hidden sometimes by default. Why do you ask for that?
EDIT: Character Encoding is there by default, but I don't know what reasons it appears - or not. I created a little AddOn for you to disable hiding which you can download at http://dl.dropbox.com/u/26332445/alwayscharset_1.0.0.0.xpi , but I won't upload it here, because I think there was a reason for it to hide per default.
EDIT2: I didn't think of that option while coding this. But I implemented it now; 1.0.0.1 is not reviewed yet, so you can only download it via the version history.
EDIT3: 1.0.0.1 is reviewed now and should get installed via automatic updates.

Rated 5 out of 5 stars

I've already tried and it didn't help. I don't use nightly tester tools, instead I use ignoring compatibility check (extensions.checkCompatibility.4.2a = false).

This review is for a previous version of the add-on (1.0.0.0). 

I still can't reproduce it. I used the preference you said (extensions.checkCompatibility.4.2a = false) in Minefield 4.2a1pre (2011-04-11) x86 on Win7 Pro x64 with a clean profile with no AddOns (except New Old Menu) or themes (except default) and installed the version before yesterday's version bump of New Old Menu - and it worked. Weird.
Do you get errors in error console when enabling / disabling New Old Menu?

Rated 5 out of 5 stars

Win7 x32.Warning: WARN addons.updates: Error: Missing updates property for urn:mozilla:extension:newoldmenu@rsjtdrjgfuzkfg.comSource File: resource://gre/modules/AddonUpdateChecker.jsmLine: 472Warning: WARN addons.xpi: Failed to remove temporary file R:\Temp\tmp-q6b.xpi: [Exception... "Component returned failure code: 0x80520015 (NS_ERROR_FILE_ACCESS_DENIED) [nsILocalFile.remove]" nsresult: "0x80520015 (NS_ERROR_FILE_ACCESS_DENIED)" location: "JS frame :: resource://gre/modules/XPIProvider.jsm :: AI_removeTemporaryFile :: line 5228" data: no]Source File: resource://gre/modules/XPIProvider.jsmLine: 5228

This review is for a previous version of the add-on (1.0.0.0). 

Could you try it again? Maybe the issue is related with the way a AddOn is installed. For testing purposes I installed a test version of New Old Menu that explicitly supports 4.2a1pre into a Minefield without internet connection. I included 4.2a1pre into official compartible versions, so it might work now (maybe you need to hit the update button or uninstall - restart - reinstall). Maybe there are nighty tester AddOns you have to have installed in order to get it to work without me changing the official compartibility list?!
Let me know if that fixed the issue.

Rated 5 out of 5 stars

I've tried a clean profile - the issue is still present.It just doesn't work properly in Fx 4.2a1pre (nightlies).Please, could you make it compatible with nightlies, if possible?

This review is for a previous version of the add-on (1.0.0.0). 

I still can't reproduce that (Minefield 4.2a1pre, 2011-04-11, x84) on Win7 Pro x64. Did you use another OS? It would be great if you can check the error console for messages related with that, maybe there is a hint what's going wrong?

Rated 5 out of 5 stars

You got me wrong. You asked what extension did I have that modifies menubar. And my answer was that it's not actually an extension, that's a button (that contains the code I previously posted) for CustomButtons extension.
I know that disabled add-on are not active, and that's why I was almost stunned when I saw that your extension actually works only when I disable it and stops working when I enable it. That's hell of a strange.
>This AddOn does not move the menubar, nor it appends it as a child to the app-menu.
I was talking about my custom button, describing what it does - it actually moves menubar to the app-button container. But once again: now I've disabled that button, but your extension is still not working for me. And the code I've posted is not wrong, it's not a code from any part of your extension, it's a code of the button I had.

You just got me wrong.

And here is a new bug I just experienced with your extension enabled. The bug has gone only after I've disabled and _restarted_ the browser. Just disabling the add-on didn't help.
The bug was that "Error Console" just disappeared from the menu and CTRL+SHIFT+J did nothing.
And yes, I had devtools.errorconsole.enabled = true in the about:config. And I haven't changed that pref at all. Disabling your extension and then restarting brought Error Console back.
Please, take a look into that.

And don't be aggressive towards me, I try to help you to fix the bugs of your extension, as I like it's idea and would like to have it working.
Just take a look yourself: http://img59.imageshack.us/img59/3250/disabled.png - this is when your extension is disabled.
http://img59.imageshack.us/img59/1441/enabled.png - this is when it is enabled.

This review is for a previous version of the add-on (1.0.0.0). 

I'm sorry we talked at cross purposes

Yes, I got you wrong. I didn't read it as answer to my answer, I read it as a new review. I'm sorry we talked at cross purposes and didn't want to sound agressive, so let's get the bug fixed:
I can't reproduce that New Old menu does work only when disabled, and I can't reproduce the error console thing. The following works for me:
1. Opening / Restarting Firefox with New Old Menu installed (-> New Old Menu changes are there)
2. Disabling New Old Menu (-> New Old Menu changes go away)
3. Pressing CTRL+SHIFT+J (-> Error console opens)
4. Enabling New Old Menu (-> New Old Menu changes appear again)
Did you try disabling other AddOns? The only AddOn causing problems I know currently is Personal Menu, but maybe you spotted another one?

Rated 5 out of 5 stars

Actually it's not even an extension, it's just a CustomButtons button with such a code:
document.getElementById("appmenu-button").parentNode.appendChild(document.getElementById("toolbar-menubar"));
e.g. it just moves menubar as a child element to the app-button.
But now I've disabled that button (so the code doesn't execute), and the extension is still not working for me.

This review is for a previous version of the add-on (1.0.0.0). 

First, this is an extension. I don't know what you think a CustomButtons is, I never heard that term, but I'm sure I coded an extension. Disabled AddOns aren't active, so there is no sense to check if it works after you disabled it. You can look at https://developer.mozilla.org/de/addons if you want more information about extensions from the developers point of view, there is a lot great stuff there.This AddOn does not move the menubar, nor it appends it as a child to the app-menu. The code you posted is completely wrong, too, you can access the correct code by unzipping the extension (xpi is a zip file with special files inside), 'bootstrap.js' in there is the relevant file. This extension changes the menu, it does not append the old one to the new one, and that is a bit more complex than a simple appendChild. If the AddOn doesn't work for you, communicate with me, so I have a chance to find the issue and fix it, if it is a issue inside the extension. You wrote about another extension causing problems in your last rating, it might help if you post what extensions you had enabed and what the exact problem is (for example 'the menu get changed in parts only' or 'the menu doesn't get restored after disabling the AddOn').

Rated 5 out of 5 stars

Doesn't work for me (latest Fx nightly), could you please fix it?
Edit: oh, it's sooo weird, but if I disable (not delete) this extension - then it actually works like it should. If I enable it again - it doesn't work. Disable again - works again. Soooo weird.
Edit2: seems like it conflicts with my other extension that puts menu-bar to title-bar, near by the AppButton. Well, then it's not that weird, as my extension uses some dirty hacks.

This review is for a previous version of the add-on (1.0.0.0). 

Could you please send me additional information?

Could you tell me what extension you used? I'd like to add it to Developer's comments section.
AddOns like PersonalMenu interfere with this because they edit the whole menu, I haven't noticed other problems yet. I try to keep the AddOn as compartible as possible, it would be great if you assist me doing that by writing a eMail (my username at abwesend.de) or editing your review. Thanks!