I missed a character there, and i don’t know if you can edit your post here. So here we go again:
{
app.beginUndoGroup("Link Stroke Color");
var myComp = app.project.activeItem;
var numLayer = myComp.selectedLayers;
var colorExp = '(expression placeholder - for code length reasons :D)"';

//==============================================================================
function scanPropGroupProperties(propGroup){ //scans the proprieties and adds expressions to the strokes
var i, prop;
// Iterate over the specified property group's properties
for (i = 1; i <= propGroup.numProperties; i++){
prop = propGroup.property(i);
if (prop.propertyType === PropertyType.PROPERTY && prop.name === 'Color' && propGroup.canSetEnabled && prop.parentProperty.name.slice(0, 6) === 'Stroke'){ // Found a property
prop.expression = colorExp;
} else if ((prop.propertyType === PropertyType.INDEXED_GROUP) || (prop.propertyType === PropertyType.NAMED_GROUP)) {
// Found an indexed or named group, so check its nested properties
scanPropGroupProperties(prop);
}
}
}
app.endUndoGroup();
}


Andrei
My Envato portfolio.

I did not test this piece of code. Now i did. Only problem i have is applying the preset. I need to use File(“\\fill.ffx”); Do you have any other code than this? Is this part of a bigger script? I can’t seem to figure out what is wrong. You are running this code inside extendscript? Or with file>script>run script?

Andrei
My Envato portfolio.

Found your problem. applyPresset applies to all selected layers. So you should deselect them all after saving your numLayer variable, and select each one when needed, then deselect it again. I ran into this problem before. I have a function that i sometimes use . So i think this should solve your problem.
{
app.beginUndoGroup("Link Stroke Color");
var myComp = app.project.activeItem;
var numLayer = myComp.selectedLayers;
var colorExp = '(expression placeholder - for code length reasons :D)"';
deselectEverything();

//==============================================================================
function scanPropGroupProperties(propGroup){ //scans the proprieties and adds expressions to the strokes
var i, prop;
// Iterate over the specified property group's properties
for (i = 1; i <= propGroup.numProperties; i++){
prop = propGroup.property(i);
if (prop.propertyType === PropertyType.PROPERTY && prop.name === 'Color' && propGroup.canSetEnabled && prop.parentProperty.name.slice(0, 6) === 'Stroke'){ // Found a property
prop.expression = colorExp;
} else if ((prop.propertyType === PropertyType.INDEXED_GROUP) || (prop.propertyType === PropertyType.NAMED_GROUP)) {
// Found an indexed or named group, so check its nested properties
scanPropGroupProperties(prop);
}
}
}
app.endUndoGroup();
}
//==============================================================================
//Go through the current active composition and deselect everything
function deselectEverything() {
var myActiveComp = app.project.activeItem;
for (i = 1; i <= myActiveComp.numLayers; i++){
myActiveComp.layer(i).selected = false;
}
}


But i still don’t know why applyPreset acts this way.

Andrei
My Envato portfolio.