Hi Claudia,

the "true": true, "false": false in the condition expander looks suspicious.. I think we can actually skip that entire block, making it:

{
    "type": "fluid.model.transform.binaryOp",
    "outputPath": "display.screenEnhancement.highContrast",
    "left": {
        "expander": {
            "type": "fluid.model.transform.binaryOp",
            "leftPath": "gtk-theme",
            "operator": "===",
            "right": "HighContrast"
        }
    },
    "right": {
        "expander": {
            "type": "fluid.model.transform.binaryOp",
            "leftPath": "icon-theme",
            "operator": "===",
            "right": "HighContrast"
        }
    },
    "operator": "&&"
}

Doing this, the result from the outer (&&-) binaryOp will be assigned to the outputPath directly, which should give us the same result as what you have above