Created attachment 87975 [details]
example demonstrating problem

Hi!
Sorry for my English.

LibreOffice-4.1.2.3 has trouble that not exist in previous versions (at least LibreOffice-4.0.4.2).

Workbook of 2 sheets: "Sheet1" and "Sheet2". Cell "A1" of "Sheet1" contains value 42. Object's reference mySheet is messed after adding sheet. First MsgBox correctly reports value 42, but second don't.

Option VBASupport 1
Option Explicit

Dim mySheet

Sub Main
	Set mySheet = Sheets("Sheet1")

	MsgBox("Before copy sheet: " + mySheet.Cells(1, 1).Value)

	Sheets("Sheet2").Copy Before:=Sheets("Sheet1")

	MsgBox("After copy sheet: " + mySheet.Cells(1, 1).Value)
End Sub

Code like above is from file generated by another program beyond our control.
Attachment contains sample file. Try to run macro bug_demo.ods -> Standard -> Module1 -> Main.