Dropdown resets to default value after callback

Dash Python
1

I’m having issue with a drop-down not maintaining it’s value when controlled from a button.

In one utility file, I have a function which returns a html.Div().

def my_div(display):
    return html.Div( id = "my-container",
        children=[
            html.Div(
                children=[
                    dcc.Dropdown(
                        id="my-selector",
                        options=[
                            {"label": "x", "value": "x"},
                            {"label": "y", "value": "y"},
                        ],
                        style={'display' : display},
                        persistence=True,
                        value= 'x',
                        clearable=False
                    )
                ],
                style={"width": "250px", "marginLeft": "16px"}
            ),
        ],
        className='filter-selector',
    )

In another index file, I have the following callback.

@app.callback(
    [Output('my-selector', 'value')],
    [Input('update', 'n_clicks')]
)
def set_squashed_point(n_clicks):
    if n_clicks >= 1:
        return "y"
    else:
        return "x"

In the UI I have a button that when clicked, successfully calls the callback, so I expect the drop-down, my-selector, to change its value from x to y and say at y, but instead goes back to x. Why is that ??

How do I get my callback to set the dropdown and stay at the value which was set ?

I am really confused about this, and would like some help.