Beforedoubleclick Create Sheet Stops Working Intermittently

I am using a BeforeDoubleClick event to look for a worksheet name and if it exists, go to the sheet. If the worksheet does not exist, it is creates a new sheet by copying a hidden sheet and naming it using a name in a cell reference. It works for the most part, but I am finding that it is having an intermittant issue. Sometimes, when I double-click, it double-clicks the target cell for editing, and then it renames the active sheet to the cell reference rather than copying the hidden sheet. It seems to happen when I reach 35 sheets created, but not always. Here is the

Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
Dim WSname As String
Dim WScheck As Worksheet
Dim WScheckname As String
If Not Intersect(Target, Range("A5:L85")) Is Nothing Then
WSname = Range("L" & Target.Row)
On Error Resume Next
Set WScheck = Sheets(WSname)
If WScheck Is Nothing Then 'Doesn't exist so create it
Sheets("Master_SLP").Copy Before:=Sheets(Worksheets.Count)
ActiveSheet.Name = WSname.........................