Windows: If the program can't start at all, you might need to install
"Microsoft Visual C++ Redistributable for Visual Studio 2015, 2017 and 2019"
which can be found here:
https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

If you have any problems, read Help -> "Problems/FAQ" inside the program.
Also read "Known bugs".

To toggle fullscreen mode, press Alt+Enter (Ctrl+Cmd+F also works on Mac).

If you selected a way too big window size by accident and can't go back, press
Alt+Enter to enter fullscreen mode, then you go to Config and press Reset Config.