In some cases, autofill writes data to the row headers, when some of the columns are before the rendered part of the table.

[jansiegel]

When using the autofill feature on a selection which:

• First element is in a column before the rendered part of the table
• Consists of columns with validation enabled
• Does not span all columns

on a table with row headers enbled, data will be written to some of these headers, causing Handsontable to crash.

Demo: http://jsfiddle.net/js_ziggle/t08mbs0s/

Steps to reproduce:

• Selected cells from B1 to T1
• Grab the fill handle and drag it downwards to apply autofill
• Scroll to the left

Result: Table crashes due to errors in the console.