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Sencha - Community Support Team
[4.0.1] The height of header is not synchronized between locking/non-locking parts
If the non-locking columns contains the group column, the header naturally takes 2 rows.
However the height of header for locked column is not synchronized and still takes only 1 row.
See the attachment (unpack to ext-4.0.1/examples/grid and open /ext-4.0.1/examples/grid/group-header-grid.html) headers-height-bug.zip