A few suggestions, if I understand the problem correctly:

1. Click the 'Melody' pull down menu.
Select 'Utilities'.
Select one of the 'Eliminate Note Overlaps'.

or 2. Ensure you are in the 'Editable Notation Mode',
Right click the offending note.
Select 'Edit Note'.
Check the 'Duration', and type in the correct the length of the note.

or 3. Use your mouse to Delete the note and then enter it again.


Grah Jive Talk
"Don't worry baby, they'll swing their arses off."