My primary language is Thai. Is it possible to customize my list with Thai difinition?

We'd be fine with adding Thai to the list of offered languages. We'd like to have a good base of definitions though; would you be interested in taking the lead on building the dictionary for it? If you start making custom definitions in Thai now, and when you have a critical mass we could then use those as the base of that dictionary.

What would be considered critical mass?

I tried putting in Thai translation for a simplified charecter but it does not seem to carry over to traditional version of the same charecter?

Something like the first two or three HSK lists, or a few beginner to lower-intermediate level lists, to make sure a good number of the more commonly studied words are covered.

It should carry over the definitions between them. What's an example of a word that's not carrying over, and where are you encountering the traditional without the custom definition?

There is a difference between a character and a character component. They are 2 different lists in Skritter. If you have a character, which is also a character component, then you might have changed the character definition, however, the component definition is still the old one, unless you also change this.

i can't remember which charecters I have done now. I will keep adding Thai translation. Let's see how I will be getting on in a few months. Btw iPhone keyboard layout isn't really Thai friendly so if you can hurry up on the iPad app it would help. ;)