Width of drawn list box? - vb.net

Question

I've created a custom combobox that uses a custom instance of a listbox control as the dropdown menu.
In order to customize the selection highlight of the listbox, I had to change its 'DrawMode' property to 'OwnerDrawFixed' and added the following code:
Private Sub _listBox_DrawItem(sender As Object, e As DrawItemEventArgs)
If e.Index >= 0 Then
e.DrawBackground()
If (e.State And DrawItemState.Selected) = DrawItemState.Selected Then
Using br = New LinearGradientBrush(e.Bounds, ColorSelectionListbox, ColorSelectionListbox, 0)
e.Graphics.FillRectangle(br, e.Bounds)
End Using
End If
Using b As New SolidBrush(ColorTextListbox)
e.Graphics.DrawString(_listBox.GetItemText(_listBox.Items(e.Index)), e.Font, b, e.Bounds)
End Using
e.DrawFocusRectangle()
RaiseEvent DrawItem(Me, e)
End If
End Sub
But with this, the width that I set for it is ignored and becomes a fixed width of 15 or so pixels.
How can I set the width of the owner-drawn control? Currently I have it as a property:
Public Property DropDownWidth() As Integer
Get
Return _dropDownWidth
End Get
Set(value As Integer)
_dropDownWidth = value
_listBox.Width = value
Invalidate(True)
End Set
End Property

Answer 1

Below is the rest of the code that is relevant, but nevermind.. I fixed the issue by setting the Autosize property of _controlHost to False. I had it set to True in order to display all items within the list (without having to define a dropdown maximum) but for some reason it behaves differently when the DrawMode is set to OwnerDraw.
_listBox = New ListBox()
_listBox.IntegralHeight = True
_listBox.BorderStyle = BorderStyle.FixedSingle
_listBox.SelectionMode = SelectionMode.One
_listBox.BindingContext = New BindingContext()
_dropDownWidth = Me.Width
_listBox.Width = _dropDownWidth
_controlHost = New ToolStripControlHost(_listBox)
_controlHost.Padding = New Padding(0)
_controlHost.Margin = New Padding(0)
_controlHost.AutoSize = False 'Used to be variable property _dropDownAutoSize
_popupControl = New ToolStripDropDown()
_popupControl.Padding = New Padding(0)
_popupControl.Margin = New Padding(0)
_popupControl.AutoSize = True '
_popupControl.DropShadowEnabled = False
_popupControl.Items.Add(_controlHost)