TStringList Property

Sorry for my english.
I defined a new action type for my TactionList and this new action type have
a TStringList type property.
I have create a property editor for this (a window opened by click on '...'
button) but can't get the value of my StringList in this window to edit

I have found how do this for 'simple' type as Float or as Enum type but
nothing for a StringList.

Regards, Sbastien (France)