There is a bug in Android 4.3 and it is said to have been fixed in Android 4.4.
How can I know how it is fixed?
https://issuetracker.google.com/u/1/issues/36985755
Update 2018/03/01:
I searched with the keyword "mCurMethod" in gerrit and seems to find the related changes to fix it.
It is the commit. https://android-review.googlesource.com/c/platform/frameworks/base/+/68103
But IMHO, it is not merged into master because of merge conflicts.
How do we know how AOSP fixes it?
Git log in framework/base seems a lot of commit and is hard to locate the specific commit.