When setting a column to 'hideable: false' with Ext.tree.Panel, the column dont 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'.

Im using ext-4.0.7-gpl, and this bug dont seems related to browsers.