How do I limit textbox to one puntiation maximum? (calculator)

I'm making a simple calculator. right now everything works fine except i can write for example "0.22.3.4.5" and i want to limit it so you can only write one point.

i have it on click add "." to variable and then set variable to textbox.

Change the condition Text is not "." with this one:

System compare two values: find(TextBox.text,".") < 0

Yay took me a bit to get it. But i did. Thanks a lot. its been a while since i last used Construct ^^.

thanks dop2000