Automatically Call Macro Based On Changed Cell Address & Text

I have the following code pasted into the worksheet module which used to work fine but no longer does. I didn't touch the code, it just stopped working.



Private Sub WorkSheet_Change(ByVal Target As Range)
Select Case Target.Address
Case "$A$16"
Select Case Target
Case "Custom Color 1": Call CustomColorInput1
Case "Custom Color 2": Call CustomColorInput1
Case "Custom Color 3": Call CustomColorInput1
Case "Custom Color 4": Call CustomColorInput1
Case Else:
End Select
Case "$A$17"
Select Case Target
Case "Custom Color 1": Call CustomColorInput2
Case "Custom Color 2": Call CustomColorInput2
Case "Custom Color 3": Call CustomColorInput2
Case "Custom Color 4": Call CustomColorInput2
Case Else:
End Select
Case "$A$18"

CustomColorInput 1-6 are the same except they input data into different cells F16-F21.

When I attach any of the CustomColorInput macros to a button it works fine. When I try to call it from the worksheet module, the data input box pops up but the data doesn't get entered into the cell. When I try to step through the CustomColorInput macros using F8, the input box pops up, I enter data and press ok. Then I continue with F8 and the debugger jumps to a custom function that I entered (below), which is not called for and is in no way related to the code.


Function PullAfterLast(rCell As Range, strLast As String)
PullAfterLast = Mid(rCell, InStrRev(rCell, strLast) + 1, 256)
End Function

When I close VBA, the data that I typed into the data input box is in the correct cell.

So basically, I'm getting three different responses from the offending code depending on how I call it up. Can anyone tell me what's going on?

More generally, in this and previous occasions, I've had problems with macros that cease to work for no reason that is apparent to me. What are some things that would cause a macro to stop working, without actually changing the code (other than the obvious, like referring to names or worksheets etc. that don't exist anymore)?