Did you add in the following as shown(?):

With Application
.VBE.MainWindow.Visible = True
...statements... (your code)
.VBE.MainWindow.Visible = False
End With

You mention that 'as far as you know, the vbe window is visible', so I am curious to know whether you were trying to step-thru the ode from the vbe window itself. If this is the case, this errored for me, as the ...properties dialog becomes focused ans upon stepping thru, the vbe window is now focused. Probably not articulate, but try running the sub from the app (workbook) window. It ran w/o a hitch for me.