Welcome @tadek.jakubow. It would be helpful to have a screen shot of what you're trying to do. If you're trying to use a comma , in place of a period . for decimals it will likely cause an error in EnergyPlus.

i know it's some kind of newbie problem, but im sure it's not about comma/period use. anyway, this gif might explain it better:

http://s16.postimg.org/f2vouqdut/imag...

Thanks for the animated gif. It clearly looks like a bug, but I can't re-produce it on my machine. I have a few follow up questions.

• What operating system are you using?
• If you make a new material and a new model do you still see this?
• Does this happen for other kinds of objects like internal loads, or is it just limited to materials?

Try saving the project before exiting that particular material. Are your changes retained?

Thank you for answer, This situation happens anytime I try to put integer value, anywhere (old and new materials, internal loads, etc.)

I'm using Win8.1, sketchup2015, openstudio 1.7.1. By now I tried reinstaling openstudio as well as downgrading openstudio to version 1.7.0, both with no effect.

Kent: I've tried it already, still resets to previous value.