QMetaObject::invokeMethod(
            theme,
            [this, theme]() {
                pendingChildUpdate = false;
                theme->updateChildren(theme->parent());
            },
            Qt::QueuedConnection);

This means that you can change the palette and potentially render a frame with half the palette out of sync.

"Event compression" is just a thing that causes difficult bugs and wastes lots of time.

If we're worried about the cost of calling setXyzColor a tonne of times indepdendently we should make the colours a separate object that can be set atomically.