Extjs 4为什么隐藏所有可隐藏的列不允许？

I noticed that a user cannot hide all columns in a gridpanel. It seems that the grid must at least display one column. I can imagine this is a nice feature, but it doesn't work quite as I expected when dealing with both hideable and non-hideable columns. It seems that the rule is that at least one I noticed that a user cannot hide all columns i