A senior XDA developer member mythtrandyr has ported the Galaxy Note 2 feature MOD to the Galaxy S2 and it’s fully working as you can see the above screenshots. This MOD also comes with icons shortcut on lockscreen, ripple effect on lockscreen and skip songs using volume keys.
This guide shows you how to install Galaxy Note 2 multi window feature on Galaxy S2, only on XXLSJ Android 4.1.2 firmware/deodexed ROMS.
DISCLAIMER: Please follow the guide at your own risk, Abhinandan Tech will not be held responsible for any errors.
1: Download multi-window MOD from here(Link in comment).
2: Copy the zip file to your phone’s internal SD card.
3: Boot into recovery mode by holding down volume up, home and power buttons.
4: In recovery mode, create a backup of your current ROM, to restore in case of errors.
5: Install MultiWindow_AllApps_LSJ.zip from recovery.
6: Reboot Phone.
Comment if you have any queries.