Right-Click anywhere on the screen, even in the left Workspaces area or in the top menu area and you will get the Right-Click menu for the Workspace appearing.
This menu will appear when clicking anywhere, except on the selected Workspace item on the left which only shows the appropriate menu.
Summary: You haven’t prevented opening of the Right-Click menu outside the main workspace directory/file panel except when clicking over the selected workspace item itself. Even the menus at the top of the screen don’t work correctly as both menus will open at the same time.
That may be true, but users don’t do what they’re supposed to
IMO, it’s not that hard to show a context menu only when clicking on the appropriate container element, I figured I’d let you know since you might have just tied it to the wrong container. shrug