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[FIXED-EXTJSIV-545][B1] Drag and Drop from Grid to Grid Example Sample Bug.
Hide a column in one grid hides the same column in the oder grid.
Only first column would happen and I would think it's because it has an id an the column config is shared between the two.
Thanks for the report. Note that this was an issue within the example.
Because the headers in a grid are actual Ext.Component's they must be unique id's just like any other component that you create.