The Shell Context Menus work great. Flash drive not connected - no shortcut menu for 7-Zip. Connect the drive - now there's a shortcut menu.
7-zip.dll is loaded as soon as you right-click something in Windows Explorer. That .dll stays loaded until you close that specific instance of Explorer. This prevents the flash drive from being removed safely until all Explorer windows that have seen a right-click have been closed.
My question is this: Is there any way to close the 7-zip.dll without closing all the Explorer windows that have used it? If so, it might be possible to automate the process when PAM closes so the drive can be removed safely.