Running adda-gui with an empty field

[inzhevatkin]

I make a field in the program without specific values. For example, I delete the value in the field for the wavelength (Lambda). The program shows me that the floor is empty, however it starts up. In this case, the wavelength is equal to the last used value. I think it's better to make sure that the program does not start at all until the user enters a value so as not to make a mistake.