On Windows 10, when the attached screen is unplugged or turned off, Windows may change the output resolution and so force Xibo for Windows to resize too.
Xibo for Windows 1.8.8 onwards detect this and will resize automatically when the TV is reconnected, however you may wish to lock the output resolution of Windows when no screen is attached by making the following registry edit.
Earlier versions of Windows 10
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration\SIMULATED_xxx
00\PrimSurfSize.cx => 1920 decimal
00\PrimSurfSize.cy => 1080 decimal
00\00\PrimSurfSize.cx => 1920 decimal
00\00\PrimSurfSize.cy => 1080 decimal
00\00\ActiveSize.cx => 1920 decimal
00\00\ActiveSize.cy => 1080 decimal
Once those keys are set, reboot for the settings to take effect.
Later versions of Windows 10
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration\NOEDID_xxx
00\PrimSurfSize.cx => 1920 decimal
00\PrimSurfSize.cy => 1080 decimal
00\00\PrimSurfSize.cx => 1920 decimal
00\00\PrimSurfSize.cy => 1080 decimal
00\00\ActiveSize.cx => 1920 decimal
00\00\ActiveSize.cy => 1080 decimal
Once those keys are set, reboot for the settings to take effect.