I would suggest that you enable the option in Preferences that will ask the user if the sticky note should really be deleted. So if a user accidentally clicks on trash button, it will not directly go to the trash memoboard.
Also, instead of using the mouse, you can probably use Ctrl+O keys to roll up and down.
Another good idea is double click on the note toolbar. If you double click on note toolbar, the note will roll up and down.
Currently it is not possible to hide any buttons.