combobox cannot be updated in event handler

[henrycs]

Wave SDK Version, OS

h2o-wave-0.22.0, Ubuntu 20.4

Actual behavior

I put a combobox in page, and try to update choices and value in another event handler, no effects, the choices and value are kept in origin state, in same event handle, I set a text widget with a new content, it's OK.
Another testing, I restore wave to 0.21.0, same code, this time the choices are updated successfully (value of combobox not updated)

Expected behavior

Choices and value updated successfully

Steps To Reproduce

My testing code:

@on('btn1')
async def on_test_clicked(q: Q):
    q.page['nav'].items[1].combobox.value = '444'
    q.page['nav'].items[1].combobox.choices = ['444', '555']
    q.page['nav'].items[2].text.content = 'button1 clicked'
    await q.page.save()

@app('/demo')
async def serve(q: Q):
    if not q.client.initialized:
        q.client.initialized = True
        q.page['nav'] = ui.form_card(
            box='1 1 3 3',
            title='Test Page',
            items=[
                ui.button(label='btn1', name="btn1"),
                ui.combobox(
                    name="change_symbol",
                    value="111",
                    choices=['111', '222'],
                    trigger=True,
                    placeholder="please input your code",
                ),
                ui.text(content="mycode"),
            ]
        )
    await handle_on(q)
    await q.page.save()