There is an issue with the right-click taskbar menu if your taskbar (Start Menu bar) is docked on the left hand side of the screen.
The context menu opens to the left of the cursor (in Windows 10), which, if your taskbar is located along the left edge of the screen, pushes the menu offscreen
If there is no display to the left of the current display, the menu is drawn completely offscreen (I only noticed it because it was changing some colours slightly on my taskbar items).
This seems to only happen if the taskbar is located along the left side - if it’s along the bottom, right, or top, the menu opens on the same display as the taskbar.
Testing some other applications in my taskbar tray, their context menus seem to all have the “open to the left of the cursor” behaviour. However, when the taskbar is along the left edge and I open a context menu from these other apps, the menu seems to move right by it’s own width before opening as part of some “edge of screen” detection (even when there is a display located to the left of the current display).
Note that the DPI scaling for both of my displays, which are at the same resolution of 1920x1080, is 100%.
I have been having this issue for some time, but did not note the context menu shoving offscreen until I recently swapped primary displays in Windows - I had chalked it up to other unresolved issues I found in these forums, where people simple worked around the problem by using the context-menu within Windows Explorer directly to make changes.