The main window used to have a panel at the bottom with several control elements and labels. Where is it?

When the software displays the main view, pressing the key ‘s’ switches the status bar on or off. Maybe you accidentally pressed this key. Do it again and the status bar will appear again.

The visibility of the status bar is saved in the program’s configuration files. When you load a configuration, the status bar might eventually disappear, depending on the settings in the file.