When objects like signals, pins, and symbol elements are selected in one window, that selection is maintained across all relevant windows. For example, the connection between signals and pins is based on pin assignments, so whenever a signal is selected in the Signals List, its assigned pin is highlighted in the Pins List. Similarly, whenever a pin is selected in the Pins List and this pin is assigned to a signal, the signal is highlighted in the Signals List.
Graphical elements of symbols do not have their counterparts in other windows, however, ports in symbols do have counterparts in signals or pins. When you select a port in the Symbol Window, the appropriate signal and/or pin is also selected in all other windows.