processEvents

pub fn processEvents(self: *ScrollContainerWidget) void {
    const evts = dvui.events();
    for (evts) |*e| {
        if (!self.matchEvent(e))
            continue;

        self.processEvent(e);
    }

    // might have changed from events
    self.frame_viewport = self.init_opts.frame_viewport orelse self.si.viewport.topLeft();
}