Why are some properties hidden in intellisense?

I'd suspect that your version of VS has become confused - it happens from time to time with me as well - my version is showing the CurrentCell property of the myDataGridView instance in intellisense with no problems.

Try shutting down VS and restarting it - chances are that will bring it back.
"Sorry what i mean is `OwningColumn` doesn't show as a property for CurrentCell yet it is one"
I just tried:

Private Sub myButton_Click(sender As Object, e As EventArgs) Handles myButton.Click
    If myDataGridView.CurrentCell.OwningColumn.Name = "hello" Then
        MessageBox("Yep!")
    End If
    If myDataGridView.
End Sub

And it was:

Type "If", space, "myD" dot "Cu" dot "Ow" dot "N" space

With each term appearing in intellisense and autocompleting as I type.

That's with VS Community 2013, on a test WinForms VB app.
So what is different?

If DataGridView1.CurrentCell.OwningColumn.Name = "Dog" then
 'Whatever
End if