Ext JS：向网格中的列添加按钮以显示/隐藏其他列

I'm trying to create the effect of "expanding/collapsing" columns in an Ext JS grid. To do this, I'd like to add an icon/button next to the name of a column, such that when somebody clicks on it, it's child columns are either hidden or shown.I'm trying to create the effect of "expanding/c