As you've found out, you can't use the MouseMove event for this as moving over an object doesn't cause it to receive the focus
I think you need to modify your approach
1. Make the Notes box taller so its obvious that there is more space to add additional text
2. Add code to the Notes_AfterUpdate event to set the focus to the Add Record button
Then 1 click will do what you want
However, do you really need the button?
You could add code to the Notes_AfterUpdate event to save the record
OR make the Notes textbox a bound field so it is automatically saved?