When you connect to the instrument using Remote Desktop, Windows must switch the graphics adapter between with physical graphics adapter in the PC/Instrument to a Virtual Graphics adapter.  When you resume using the instrument the graphics adapter must switch between the virtual graphics adapter and the physical adapter in the PC/instrument.  During this switch, sometimes the sub-system which draws the Waveform Graticule does not get updated to the change and the Graticule appears blank.  This issue can be remedies easily by left-click and holding the title bar of the TekScope Window and moving it as this is enough to trigger the update to the sub-system.  Alternatively you can close and restart the TekScope application.