How to use chatheads on Facebook app with Messenger app installed

Facebook said they started forcing people to use the Messenger rather than allowing to use chatheads within the Facebook app. I got my messages tab on Facebook disabled almost a month ago. This is quite annoying, having to switch to another app to say "Hi". It also causes to lose the flow while browsing newsfeed. The problem gets severer on devices like iPhone 4S and iPhone 4. The time it takes to switch to the other app and the memory it requires to run in the background totally ruins the experience. I know many people who have quitted using Facebook app and switched to using a browser instead. It's the memory that can be used to run other useful apps in the background, this Messenger app reasonlessly uses. Therefore Facebook's philosophy of 'faster messaging' is simply absurd.

Well, we have a solution. There used to be a Cydia tweak to disable Messenger detection but it's no longer to be found. The FLEX patches don't seem to work either. Today, I took the challenge and started finding a solution. First I tried cloning the app and changing the bundleid and things like that. Remember that I'm not a programmer. Anyway, after countless attempts, I found a solution
I'm a Windows 7 user, so I'll explain how to do it on Windows

Prerequisites

• Appsync for iOS 7.0+
• iFile on iDevice or  plistEditor pro on Windows
• iFunbox 

Step 1 : Dismantle the Messenger app

• Go to the iTunes library folder (normally "C:\users\%username%\My Music" or Libraries> music on the windows explorer left pane)

• IPA files are actually ZIP containers with a different(*.ipa) extension. Rename the file and put the extension 'zip' instead of 'ipa"

• Extract the whole archive to somewhere else

Step 2 : Modify the Info.plist

• Inside the main folder, you can find a 'payload' folder which contains the 'messenger.app' folder. Open it and find the "Info.plist" file

• You cannot open '.plist' files on Windows by default. Either get 'plistEditor pro' or copy the plist file to iFile and edit on iDevice

• Find the following inside the file

  <dict>
<key>CFBundleURLSchemes</key>
<array>
<string>fb-messenger-neue</string>
</array>       
 </dict>

• Select and delete these lines and save the file

Step 3: Repacking Messenger

• Select all the contents in the main folder 

• Zip them
• Rename and change the extension from '.zip' to '.ipa'

Step 4: Load Messenger

• Delete the original messenger app on device if you already have it installed
• Open iFunbox > iFunbox classic > Install app
• Browse and select the modified Messenger app

IFunbox will install the modified messenger successfully if you have appsync 7.0+ installed on device