Interesting, pasting into the collapsed subprocess (and not in its plane) works by:
var context = evt.context,
element = context.shape,
businessObject = element.businessObject;
// const parent = targetElementRegistry.get(businessObject.id + '_plane');
// remember size of collapsed subprocess shape
var x = element.x,
y = element.y,
height = element.height,
width = element.width;
var pasteContext = {
element,
// element: parent,
// element: targetElementRegistry.get('Process_1'),
point: {x:100, y:100}
};
// paste tree
targetCopyPaste.paste(pasteContext);
// restore size of collapsed subprocess shape
modeling.resizeShape(element, { width, height, x, y } );
Unfortunately, a workaround is needed to restore the size of the element, so the solution is probably not perfect.
@nikku: This is almost the same problem as discussed in Programmatically populate collapsed subprocess - #3 by nikku but using the element referring to the subprocess plane doesn’t work in this case