copy cells across 120 rows causes a javascript error

Steps to Reproduce

1. run

<spreadsheet id="ss"  src="/WEB-INF/excel/blank.xlsx" maxVisibleRows="300" maxVisibleColumns="50" width="100%"
		height="90%"
		showContextMenu="true" showSheetbar="true" showToolbar="true" showFormulabar="true"
 />

2. paste cells from excel over 120 rows, e.g A1:A120

Current Result

zss.wpd:6733 Uncaught TypeError: Cannot read property 'getCell' of undefined
at init._isProtect (zss.wpd:6733)
at init._speedCopy (zss.wpd:6770)
at fn (zss.wpd:16901)
at init.onResponse (zss.wpd:957)
at _invoke (zk.wpd:12829)
at init.fire (zk.wpd:12812)
at zk.wpd:12950

Expected Result

no such error

Workaround

• increase preload row /column size