Thank you for writing.
Best fitting the columns is a complex operation requiring measurement of all the data in the grid. When dealing with columns, as in your scenario, it may take time before the grid refreshes with the adjusted widths.
In our Q3 2015 release, we have improved this performance: Feedback Item
. If it is possible please upgrade your version of the suite.
I hope this helps. Should you have further questions please do not hesitate to write back.
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