[mobama]

Looks like I discovered a disastrous thing in Koreader: When you highlight some text in a pdf and then save it, the file gets irreversibly altered. There seems to be no way to unhighlight. Some tap on the altered place seems to occasionally give you the "delete" option, but it has no lasting effect the way highlight does.

I know that the file is permanently altered because when it opens up in the default reading app, the same place looks the same as in Koreader.