Hi

Insert a userform with a combobox and a command button.

in the userform module put this code.

Code:
Option Explicit

Private Sub CommandButton1_Click()
    
    ActiveCell.Value = CDate(Me.ComboBox1.Value)
    Unload Me
    
End Sub

Private Sub UserForm_Initialize()
    
    Dim Dt()    As String
    Dim n       As Long
    Dim cDt     As Date
    Dim sDt     As Date
    
    sDt = Date
    Select Case ActiveCell.Column
        Case 4
            ReDim Dt(1 To 31)
            n = 1
            Do While sDt >= Date - 30
                Dt(n) = Format(sDt, "mm-dd-yyyy")
                sDt = sDt - 1
                n = n + 1
            Loop
            With Me.ComboBox1
                .List = Dt
                .ListIndex = 0
            End With
        Case 6
            ReDim Dt(1 To 15)
            n = 1
            sDt = Date - 7
            Do While sDt <= Date + 7
                Dt(n) = Format(sDt, "mm-dd-yyyy")
                sDt = sDt + 1
                n = n + 1
            Loop
            With Me.ComboBox1
                .List = Dt
                .ListIndex = 7
            End With
    End Select
    
End Sub
Right click TASKS worksheet > view code and paste the following code

Code:
Option Explicit

Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As Boolean)
    
    Select Case Target.Column
        Case 4, 6
            Cancel = True: UserForm1.Show
    End Select

End Sub
Now right click on Col 4 or 6, the userform will popup with a set of dates and select one date hit the command button.

I can't upload a file that's why this detailed explanatin.