Are you using a form rule or a runtime expression within the control?

I think the best way to accomplish what you want is to have a rule. You can click "add rule" in the ribbon once you've selected your control:

And then format it like this:

by clicking the f(x) next to the condition you can get your usual settings like Is New Mode and such. Make sure you check the "disable" box!

Yes, this variant works, but a little bit in other way that it were.

Main question, that it worked before update on new version of Nintex form, and still works for other types of fields.

Variant that you proposed works and block text input, but it's look like ready for input.

But if we block in my way it just grey color for text display.

Hmm, that display behavior must be a difference between 365 and 2013. Checking the release notes here:   I don't see the version you've listed above. Perhaps some 2013 gurus like  or  or  could be of further assistance on that front.

But it's 365 version.

Hmm, that's interesting. Mine displays grayed out when I use that function and I am also in 365.