coloring imported drawings

Why I can’t color or modify any drawing imported as a bitmap and “vectorized” as in Studio

If you import and vectorize with color in Animate using default option (not color vectiorization), the result is exactly same in Toon Boom Studio option of import ‘with texture’. However, it will be imported as a symbol, you need to double click the drawing in the time line to access to the symbol. Then rests of them are exactly same as in Toon Boom Studio.