Steps to Reproduce

1. run
<spreadsheet hflex="1" vflex="1" showContextMenu="true" showSheetbar="true" showToolbar="true"
showFormulabar="true" showSheetTabContextMenu="true"/>
2. "New Book"
3. create 2 sheets
4. input "myvalue" at A1
5. copy A1
6. delete sheet1
7. paste at sheet2

Current Result

SEVERE:
java.lang.IllegalStateException: doesn't connect to parent
at io.keikai.model.impl.SheetImpl.checkOrphan(SheetImpl.java:1518)
at io.keikai.model.impl.SheetImpl.getBook(SheetImpl.java:178)
at io.keikai.range.impl.RangeImpl.getBook(RangeImpl.java:187)
at io.keikai.range.impl.RangeImpl.isWholeRow(RangeImpl.java:772)
at io.keikai.range.impl.PasteRangeImpl.isWholeRow(PasteRangeImpl.java:41)
at io.keikai.api.impl.RangeImpl.isWholeRow(RangeImpl.java:422)
at io.keikai.ui.impl.ua.PasteHandler.processAction(PasteHandler.java:104)
at io.keikai.ui.impl.ua.AbstractHandler.process(AbstractHandler.java:63)
at io.keikai.ui.impl.DefaultUserActionManagerCtrl.dispatchKeyAction(DefaultUserActionManagerCtrl.java:411)
at io.keikai.ui.impl.DefaultUserActionManagerCtrl.onEvent(DefaultUserActionManagerCtrl.java:522)
at io.keikaiex.ui.impl.UserActionManagerCtrlImpl.onEvent(UserActionManagerCtrlImpl.java:324)
at io.keikai.ui.Spreadsheet$4.onEvent(Spreadsheet.java:532)
at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:3184)

Expected Result

paste nothing without errors