I am having an issue with public global variables that appear to be
reinitialized without execution of a specific line in the code to do
so. The variables are declared in Module1 as public (global)
variables using the following code:

Public alpha As String
Public beta As String
Public delta As String
Public epsilon As String

The values of these variables are set in the Workbook_Open() event of
the ThisWorkbook object using the following code:

alpha = ChrW(945)
beta = ChrW(946)
delta = ChrW(948)
epsilon = ChrW(949)

If I open the workbook and immediately run the Routine2 subroutine
(which uses the variables alpha, beta, delta and epsilon), it works
correctly because the values of the variables are as they were set by
the Workbook_Open event. However, the second time I run Routine2, it
does not function as expected because alpha, beta, delta, and epsilon
have been reinitialized to null values. There is no code to change
the values of these variables other than in the Workbook_Open()
event. I have added a MsgBox to check the value of alpha at the first
line of Routine2 and the last line of Routine2. The first time I
execute Routine2, alpha is equal to the value I intend at the first
line and at the last line of the subroutine. The second time I
execute Routine2, the variable has been reset to null by the time the
first line of Routine2 executes. Routine2 is executed by clicking a
command button. No code that I have written executes between the
first click of the command button and the second click of it. I can
solve the problem by setting the values of alpha, beta, delta, and
epsilon at the beginning of Routine2. However, I find it disturbing
that the global variables are somehow getting reinitialized, and I
would like to understand the underlying cause to avoid this issue in
future programming. The reason why I declared these variables as
global was so that I would only have to set their values one time,
upon first opening the workbook.