Tidy Notes attempts to present a cleaner representation of the note data. A performance does not always equal the printed sheet music.
For example, if you played a quarter note but shortened the note by a 32nd note duration, then the software would show a dotted 8th note tied to a 32nd note with a 32nd rest. This would look like the following.
To remedy this situation, simply set the Tidy Note level to an 8th note or less.
After changing the Tidy Note level, the note will now look like a quarter note.
The draw back is that if you have some 16th notes, they will now appear as 8th notes. Of course, you can always set the Tidy Note level to 16th notes and then edit any piano bars that are not correct.