XDA Forum Member xperiacle began a thread with an idea that altering a certain part of the CSC file can allow multi window support for apps that don’t usually have it. This would mean that users can make a few simple CSC edits and have their apps work without any mods required. As xperiacle explains:
I came across a smali code fragment that checks for multiwindow supported apps in CSC file as well as excluded apps so I tried to investigate further and found out that you can actually add multiwindow support for almost any app by just adding it’s package name in feature.xml or other.xml in /system/csc folder.
Users have been trying this out and experimenting with similar alternatives. So far, the results have been mixed. However, a few have finally managed to get the ball rolling. It’s slow going, but a few have managed to get Dropbox working as a multi window app without altering the Dropbox APK itself.
To see more and stay apprised of the latest updates, please visit the original thread. Just make sure that once you start modifying your own CSC that you keep a backup in case something goes awry. In fact, it may be a good time to go about making a Nandroid of your /system partition for easy recovery.