As PD Diary was designed for people with Parkinson's, there are some features specifically to help with those people suffering from tremor.
1. PD Longclick mode - if you find that you accidentally tap or click on items that you were not intending to tap or click on, then this mode will help you. When this is turned on, many of the places where you would just tap to select, become long-tap selections where you have to tap and hold the item before it will be selected. This can help prevent accidentally selecting the wrong item.
2. PD Confirm mode - if long-tapping an item is difficult for you, perhaps this option will help. If you often click the wrong item by accident, you can turn this on to have PD Diary ask you to confirm your selection. This may slow you down as you use the program, because you have to confirm your selections, but will help ensure that you are getting the correct selection.