Comment 58 for bug 307680

I aggree with comments 8 & 13. Marking a repeating task as completed should create a single non-recurring instance of that task and mark that instance only as completed; the repeating task itself should then be adjusted to the next repeat date.
This leaves a permanent trace of when each instance was completed, including any notes, etc.. pertaining to that instance.
The current behaviour of marking all instances complete is unacceptable (on a personal note, I almost missed a mortgage payment because of that).