I do not know if this is just an issue on my PC but when I try to place a static object belonging to certain categories (i.e. the sandbag walls or ammunition crates) and switch to 3D mode to place it properly I cannot switch back to FMB because the menu bar and all the windows I opened disappear. I can only return by going back to 3D Mode, deleting the object and hoping that some other "non-affected" object gets selected. That or shutting down CloD via Task Manager.