When setting a column to 'hideable: false' with Ext.tree.Panel, the column don´t show on the column list (expected, works like Ext.grid.Panel till here) and the next one is disabled (greyed out - I think this is the old behaviour on 3.x if I recall it right), rendering 2 columns 'unhideable'.

I´m using ext-4.0.7-gpl, and this bug don´t seems related to browsers.