I already had three toggle buttons which I gave names in the same order as you did. Volopdek, Tussenliggend and Halfopdek.
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I put this code in the up script from button ''volopdek'': scr.setProperty('Halfopdek','Button State','Up') scr.setProperty('Tussenliggend','Button State','Up')
This is my first time trying to change screen related items in lua, so maybe I am doing something stupid here.