Now I got it working by only creating the local parameters (HIDE_WINDOW_A, HIDE_WINDOW_B, ...) and giving them a default value '0' in the connections table.
Then in the button's and windows which are to be hidden I used these newly created local parameters directly. (instead of using the $T).
And now it is working fine. :-)... still don't know what I'm doing wrong when using the connections table....

thanks for you feedback. I can see that our documentation is not enough. Please, see the example attached:
0301_Human_Machine_Interface_HMI.zip

Let me know if there is still missing something.

Cheers,
Tomas

Yes, I have seen this document but somehow I cannot get it working. After a while I started to create all kind of possibilities and none of them worked. The funny thing is that I already managed to do this in the past but I didn't saved it...

So for the button I should use the alias HIDE (between curly brackets?) and is it 'W' or 'L' ?
And the object which's opacity needs to be changed is then also the alias HIDE, inbetween brackets and 'R'? Or is 'L'.
Is it important in which order the parameters are assigned in this table?

thanks for question. Did you look into the HMI docs? The Local items are mentioned here: https://www.rexygen.com/doc/ENGLISH/MANUALS/RexHMI/RexHMI_ENG.html#x1-120003.2.1

You just need to specify Alias (used in button as control and other components as HIDE parameter), Default value (Connection String column) and type = L - see the Figure 3.3 in above mentioned docs.

Let me know if it helped.

Kind Regards,
Tomas