Symbol doesn't update

I use TB Harmony now but i came from TVPaint.

My question is:
I use a symbol and put it in the camera view. Than i go back to the symbol and make new drawings, many drawings, so the symbol has a new duration.
When I go back to the camera view, the duration of the symbol in the timeline hasn’t changed.
I have to delete the symbol and put it again in the camera view.
It slow down the workflow.
Is there a possibility, to update the length of the symbol in the camera view?