The Simulator Control Panel allows you to control every object in the simulator, with additional buttons for controlling properties of the simulator objects.

The most important details are on the top left, primarily the floor you're on, which in the example is floor 0 (with 1 being the floor's ID).

Since Skyscraper supports running multiple buildings simultaneously, the Control Panel window only shows the information for the current simulator engine.
To switch simulators/buildings, use the Engine Manager feature.