If LXDE is used in a guest OS in VirtualBox, the position of the lxpanel should adjust if the user resizes the VirtualBox window (i.e. virtual monitor). This is currently not the case. To trigger the correct positioning of the lxpanel (several) mouse click is needed on the desktop.
To reproduce use LXDE in VirtualBox, install guest additions and resize the VirtualBox window with a mouse.