Timeline: How can I disable browser series' color fill?

Hi there,

I have been trying to disable this fill color from the browser view with the following code:

tl.setBrowserFillColor(cont, null);

because I read somewhere (don't remember where) passing a null would disable it but it did not work. Then I checked the implementation and effectively null doesn't disable anything but assigns fixed color.

if (color == null) {
                color = new SolidColor(0xED, 0xF7, 0xFF);
            }

Is it even possible to do this? I would like to see all my series in the browser as well.

Note: I have attached how it looks and the code which generates it.
Edit: Vaadin 7.5.4 and Charts add-on 3.0.0-alpha4