If some of your client machines have multiple monitors and others do not, you may not be able to see some of your windows when you move between machines.
If you are logged in on a machine with multiple monitors and close a window, e.g., the item, asset, or employee list, while it is positioned on a second monitor, then log in as the same user on a different machine which only has a single monitor, the window will still try to display on the second screen, and will therefore not be visible.
If you have this sort of mixed environment and move between machines, make sure to always position your windows on the primary monitor before closing them.
This affects all current Wasp products (InventoryControl 5.3, Mobile Asset 5.5, WaspTime 6.1) and prior versions. It will be corrected in future versions of the programs.