Indesign eyedropper tool

My two cents: many features are included in both Illustrator and InDesign, but work differently. 

You may find drag and drop colors useful to get where you want to go. You can drag saved swatches, but also just color that appears at the top of the Swatches panel (stroke or fill). Keep a close eye on the cursors: the \ under the arrow indicates you will change the stroke, the solid square indicates you will change the fill.

~Barb

I just got chatgpt to write a script to do it. If anyone comes across it in the future and is interested, code is below. Select the object you want to change first, then shift select the second object for the reference you want the colour from. Then run the script. 

// ApplyColorAutoReversed.jsx

// Automatically apply fill or stroke from the last selected object to all other selected objects

if (app.documents.length > 0) {

    var sel = app.selection;

    if (sel.length >= 2) {

        var source = sel[sel.length - 1]; // last selected object = source

        var targets = [];

        // All other selected objects = targets

        for (var i = 0; i < sel.length - 1; i++) {

            targets.push(sel[i]);

        }

        for (var j = 0; j < targets.length; j++) {

            var target = targets[j];

            // Apply Fill → Stroke if possible

            if (source.hasOwnProperty("fillColor") && target.hasOwnProperty("strokeColor")) {

                if (target.strokeWeight === 0) target.strokeWeight = 1;

                target.strokeColor = source.fillColor;

            }

            // Apply Stroke → Fill if possible

            if (source.hasOwnProperty("strokeColor") && target.hasOwnProperty("fillColor")) {

                target.fillColor = source.strokeColor;

            }

        }

    }

}

Sample the piece with while holding down the Alt/Option key 

Then click on the piece you want to apply to.

And yes, I believe the behaviour is different to Illustator.