I wanted to create some script for my button. Following this [www.sidefx.com] post I found that I have to add some script to operator properties. But after adding simple python script and pressing "Apply" some weird errors popped out, such as "some parameter have global reference" and showing me material references. But shouldn't material references be always global? Anyways. After that I found all my nodes locked for editing + all my scene geometry missing.
P.S. when I open all other geometries, I see content of geometry node I was editing.

You've saved an HDA called 'geo' that has replaced the definition for new empty geometry containers. Now all objects will be this new type instead of containing their original contents. I hope you have a backup scene file, because you're going to have to delete this HDA to make houdini usable again.

Yes, fortunately, I haven't saved this messed file so it was successfully reverted.