VBA Code takes too long to Run - vba

Question

Please see the below VBA Code that I've came up with. Essentially, this is to open another workbook, Unmerge the Rows, Copy the Columns and Paste it into my Active Workbook. However after copy pasting, when the code runs to the CalculationAutomatic line, it takes around 15mins. Is there any other way to make it more efficient?
Thank you
Option Explicit
Sub ImportRemarks()
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False
Dim PLPath As String
PLPath = Sheets("Instructions").Range("C16").Text
Dim wbThis As Workbook
Dim wbTarget As Workbook
Set wbThis = ActiveWorkbook
Set wbTarget = Workbooks.Open(PLPath)
wbTarget.Worksheets("Performance List").Select
Rows("1:2").Select
Selection.UnMerge
wbThis.Worksheets("keys").Range("I:I").Value =
wbTarget.Worksheets("Performance List").Range("F:F").Value
wbThis.Worksheets("keys").Range("J:L").Value =
wbTarget.Worksheets("Performance List").Range("P:R").Value
wbThis.Activate
Application.CutCopyMode = False
wbTarget.Close savechanges:=False
ActiveWorkbook.Sheets("Instructions").Select
Range("C22").Select
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
End Sub

Answer 1

Maybe something like as follows for starters. Ideally, the optimization steps would go in their own subs. One to switch on optimization at the start and the other to return everything to how it was at the end (or on error).
As requested, this shows you how to remove the .Select parts of your code by using With statements. It also includes a safe exit, in case of error, to switch back on everything you disabled.
Option Explicit
Public Sub ImportRemarks()
Dim PLPath As String, wbThis As Workbook, wbTarget As Workbook
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False
Application.EnableEvents = False
On Error GoTo Errhand
Set wbThis = ThisWorkbook
Set wbTarget = Workbooks.Open(PLPath)
PLPath = wbThis.Worksheets("Instructions").Range("C16").Text
wbTarget.Worksheets("Performance List").Rows("1:2").UnMerge
With wbThis.Worksheets("keys")
.Range("I:I") = wbTarget.Worksheets("Performance List").Range("F:F")
.Range("J:L") = wbTarget.Worksheets("Performance List").Range("P:R")
End With
wbTarget.Close savechanges:=False
With wbThis
.Activate
' .Worksheets("Instructions").Range("C22").Activate '<=consider whether this is needed?
End With
Errhand:
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
Application.EnableEvents = True
End Sub
More info on optimization here:
https://www.thespreadsheetguru.com/blog/2015/2/25/best-way-to-improve-vba-macro-performance-and-prevent-slow-code-execution
http://www.cpearson.com/excel/optimize.htm