Set a value to the checkbox when Grid is set to SelectionMode.MULTI

We just got a requirement from the user to set a value text of Select All to the check box when Grid is in multiselection. I've already checked the grid and noticed the columns method just return the columns from the container i set, I'm using a Bean ItemContainer. 

I was able to implement this one using the following css selector, i know it's a hack but couldn't find out how else to do this.

.v-grid-cell > .gwt-CheckBox label:before{ content:'Remove all'}