Why can't I see dashed box represents visual design in widget blueprint editor?

[user_a16e7bb56b33a688fc5d74d5197edd2518a0ca5da82ec58f2eebe5 (社保部部长)]

The first pic is mine, the second pic is copied from official documentation

[ClockworkOcean]

Try putting a canvas panel in?

[user_a16e7bb56b33a688fc5d74d5197edd2518a0ca5da82ec58f2eebe5 (社保部部长)]

Thanks, I’m an fool