Expanding mobile sub-menus using Title

I have been using Both at to assess my site’s useability and I have noticed quite a few mobile and tablet users struggle to expand sub-menus.

People automatically click on the menu title at the left, instead of the ‘+’ on the right. When that doesn’t work they give up.

Is there any way to alter the behaviour of the mobile menu, so clicking anywhere on the line expands the sub-menu?

Apologies if this has been answered elsewhere, I can’t find a post dealing with this.

Thanks for your help.

Ian