Steps to Reproduce

1. load a blank sheet
2. copy any text from another app ,e.g text
3. click a cell, press Ctrl+v to paste

Steps to reproduce: case2

1. set <spreadsheet onCellFocus=""/>
2. double-click a cell, enter the edit mode
3. press enter to leave the edit mode
4. press Ctrl+v to paste

Current Result

no text paste

Expected Result

copied text is pasted

Debug Information

• sometimes, it might paste the text, but most of the time it doesn't paste.
• onCellFocus="org.zkoss.lang.Threads.sleep(20)", when the listener takes more than 20ms, the bug happens. The same rule applies on onCellSelection listener
• 5.3.0 doesn't have this bug

Workaround