It gets thicker...

I want to learn the methods of rylo, but as I quickly understood yours, Greg M, I did the following...

Private Sub Worksheet_Activate()

Dim PeriodArray() As String
dog = Worksheets("COS - Monthly").Range("Q_Period").Columns.Count

ReDim PeriodArray(dog, 2)

Count = 1
DeCount = 1
    For Count = 0 To dog - 1
        PeriodArray(Count, 1) = Worksheets _
            ("COS -  Monthly").Range("Mon_MC_1b").Offset(-1, 6 + Count)
        PeriodArray(Count, 2) = Worksheets _
            ("COS - Monthly").Range("Mon_MC_1b"). _
            Offset(-1, 6 + Count).Column
    Next Count

' To check my work    
'    For DeCount = 0 To dog - 1
'        Debug.Print PeriodArray(DeCount, 1)
'        Debug.Print PeriodArray(DeCount, 2)
'    Next DeCount

    ActiveSheet.cbQPeriod.List = PeriodArray()

'
End Sub
Instead of a listbox I chose a combobox because it gave me a single choice in the box in it's "unactivated" state, and when the arrow was clicked it gave me a drop-down selection. I was unable to do that with the list box. Also something I can't understand is that I tell the cb (as was the case in the lb) there are two columns, I must bind column 1, but the month data appears to be in the second column for if I set that one to a 0 width ("31.95 pts; 0 pts" instead of "0 pts; 31.95 pts"), no more month. I am probably struggling with learning the concept of a two-dimensional array, I suspect, and the model I have in my head just ain't quite right.

Anyway, those are the curiosities to me. The real question is now that someone selects a month in the display, how do I determine at what position in the 2-D array it is at so I can extract the column?

I can always revert to doing a .Find in the range, but this is as much of a learning exercise to understand arrays better. Then I get to tackle some of the "rylo concepts"...

btw, the offsets, as you probably quickly figure out, are simply to provide the proper offset to read in the horizontal data.

I have been toying with the change event of the cb, but am having a difficult time locating anything that returns my place in the array. And I have an awful feeling in my head that both of you are laughing at how complicated I may have made this for myself, but hey, btdt (been there, done that) ...

As always, great appreciation.
-Bruce