I can't open a userform from a main userform - vba

Question

I'm Using Excel 2013 vba. I have 2 Forms: frmMain and . In frmMain, I only have a cmd button with a code UserForm1.show ,however i can't open the UserForm1.
Here's my code:
Private Sub Workbook_Open()
Application.Visible = False 'This code hides the workbook
UserForm1.Show 'Brings the UserForm
End Sub
'Module1 Code..
Sub hidden()
Sheet1.Visible = False
End Sub
screenshot of my UserForm1
Code for UserForm1...
'Application.ScreenUpdating = False
'Sheets("Sheet1").Visible = True
Private Sub cmbCalltype_Change()
'==========sayon rani dri=======
'If cmbCalltype.List(cmbCalltype.ListIndex) = "Training" Then
' cmbGc.Enabled = False
'ElseIf cmbCalltype.List(cmbCalltype.ListIndex) = "Wrong GC" Then
' cmbGc.Enabled = False
'ElseIf cmbCalltype.List(cmbCalltype.ListIndex) = "Wrong Number" Then
' cmbGc.Enabled = False
'ElseIf cmbCalltype.List(cmbCalltype.ListIndex) = "Resident" Then
' cmbGc.Enabled = False
'Else
' cmbGc.Enabled = True
'End If
If cmbCalltype.Text = "Training" Then
cmbGc.Enabled = False
ElseIf cmbCalltype.Text = "Resident" Then
cmbGc.Enabled = False
ElseIf cmbCalltype.Text = "Wrong GC" Then
cmbGc.Enabled = False
ElseIf cmbCalltype.Text = "Wrong Number" Then
cmbGc.Enabled = False
Else
cmbGc.Enabled = True
End If
End Sub
Private Sub cmdApplicationshow_Click()
Application.Visible = True 'This will open the excel file...
End Sub
Private Sub cmdClear_Click()
'==========sayon rani dri=======
'Call UserForm_Initialize
txtName.Value = ""
cmbCalltype.Value = ""
cmbGc.Value = ""
cmbVisit.Value = ""
End Sub
Private Sub cmdHidden_Click()
Application.Visible = False 'This will open the excel file...
End Sub
Private Sub cmdMove_Click()
'Dim emptyRow As Long
'Sheet1.Activate 'Make Sheet1 active
'emptyRow = WorksheetFunction.CountA(Range("A:A")) + 1
'Transfer information
'Cells(emptyRow, 1).Value = txtName.Value
'Cells(emptyRow, 2).Value = cmbCalltype.Value
'Cells(emptyRow, 3).Value = cmbVisit.Value
With Sheet1
With .Range("A" & .Rows.Count).End(xlUp)
.Offset(1).Resize(1, 4).Value = Array(txtName.Value, cmbCalltype.Value, cmbGc.Value, cmbVisit.Value)
End With
txtLeasing.Value = Application.CountIf(.Columns(2), "Leasing") 'counting the number of instances leasing text occur
txtGc.Value = Application.CountIf(.Columns(3), "Yes")
'txtYes.Value = Application.CountIf(.Columns(4), "Yes")
'txtNo.Value = Application.CountIf(.Columns(4), "No")
txtPercentage.Value = txtGc.Value / txtLeasing.Value * 100
''==================
txtVisLeasing.Value = txtLeasing.Value
txtTotvisit.Value = Application.CountIf(.Columns(4), "Yes")
txtVisitper.Value = txtTotvisit.Value / txtVisLeasing * 100
End With
End Sub
Private Sub UserForm_Initialize()
'Worksheets("Sheet1").Activate
'Sheets("Sheet1").Visible = False
txtName.Value = "" 'Empty Customer
cmbCalltype.Value = "" 'Empty Call Type
cmbGc.Value = "" 'Empty GC
cmbVisit.Value = "" 'Empty Visit
cmbCalltype.Clear
With cmbCalltype
.AddItem "Leasing"
.AddItem "Training"
.AddItem "Resident"
.AddItem "Wrong GC"
.AddItem "Wrong Number"
End With
cmbGc.Clear
With cmbGc
.AddItem "Yes"
.AddItem "No"
End With
cmbVisit.Clear
With cmbVisit
.AddItem "Yes"
.AddItem "No"
End With
txtName.SetFocus
End Sub

Answer 1

Is the instance of UserForm1 called from Workbook_Open() same as the instance of UserForm1 called from frmMain ?
If Yes, then create a Module and declare the instance of UserForm1 in Module1 as Public.
If No, then declare a form level instance of UserForm1 in frmMain.
Something like below.
'frmMain Code
Dim fUser As UserForm1
Private Sub CommandButton1_Click()
If fUser Is Nothing Then
fUser = New UserForm1
End If
fUser.Show
End Sub