That is due to how Windows automatically resizes windows when you drag the window. To have the window be automatically placed in there, you will need to set the coordinates of that location in the config file of the G5. Full details are available here: https://torquesim.atlassian.net/wiki/spaces/G/pages/197208/G5+acfConfig.cfg+Description (please note, this page has been updated for 1.1 which is coming in the next few days, if you don't see some of the things shown on this page yet in your config file, don't fret)
The key values you will want to set are:
g5_nbzl_open_at_launch_a = 1 (and _b for the HSI) This will automatically open and pop-out the window at launch. Set this to 1
g5_nbzl_x_a = **** (and _b for the HSI) Set this value to the global screen coordinate of the left side of the G5 monitor, as configured with Windows.
g5_nbzl_y_a = **** (and _b for the HSI) Set this value to the global screen coordinate of the bottom side of the G5 monitor, as configured with Windows.
With these all set, the window should automatically popup and position itself when the plugin is loaded. It will take a bit of fiddling around to get the right coordinates, but once it is set, it should work great!