Abilty field doesn't let me enter large numbers

[Elfis]

The Eat Tree ability defaults to 500 HP healed... but when I gave it multiple levels and tried to change the values, the highest value it will accept is 300. How to fix?

Edit: The response below solved it. Holding down shift and double clicking the entry allows me to enter large numbers. Still curious if there's a way to possibly make it accept large numbers by default?

 

[Hermit]

Try holding the shift key while opening the field.