You can't open and close worksheets only workbooks. You have to be careful
when copying worksheets. This is what microsoft says in the VBA help

If you don't specify either Before or After, Microsoft Excel creates a new
workbook that contains the copied sheet.

You are creating new workbooks because you didn't use the before or after.

"Art" wrote:

Hi,

When I'm working on a project that opens and closes other worksheets an
entry appears in my Project Explorer -- often many of them with the same
name. Is there any way to stop this or to clear it out? Or am I the only
one having this problem? I have to periodically shut down Excel and restart
it.

I'd appreciate any advice.