ardeedae

Yes, it was error in Javascript. Problem solved, thank you very much!

But the thing is that there was no update when it disappeared. I updated it later, but only title of that widget appear on main dashboard.
I followed that instruction anyway, and checked it in two other browsers, nothing changed.

Oh, yes. Right. Thank you. Sorry.

OMG, thank you so much!

Solved, thx, I finally found simmilar question with proper explanation here.
Sorry for this mess.

Thank you, it’s not all but enough.