An IME session must be discarded when its text content no longer matches
the underlying text component content. However, the check for matching
was too pessimistic; the IME session would be discarded if the new
snippet from the text component was not equal to the snippet reported to
the IME. This change implements a refined check that only discards a
session if the content of the overlap between the new and old snippets
don't match.
Fixes an IME issue reported by Zhang Zj.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur