Inside the view top/bottom bars you can filters. Filters are a set of switches that allow you to control the type of items currently present inside the view. Must like searching allows you to only display items with certain name filters allow you to only display items with certain type.

Object and layer views contain different type of filters than schematic views but in all other respects the functionality is similar. Hover over the filters to see the type of objects that it enables. Click on the filter to toggle it on or off. By default filters are disabled (that is items of their type are present in the views).

The current filter configuration will be remembered the next time you restart your scene so you can have different views setup with different filters and thus have different behaviour.