Click "west toggle slide" or "east toggle slide" (Both are the same)
When clicking the collapsed region bar (not button) / anywhere on the page, it would trigger an onSlide event.
Using server side setSlide(false), it triggered an onSlide event.
An onSlide (slide = false) event triggered
Both true and false events are not triggered. Since they are not user's interaction.
Represents an event cause by user's slidedown or slideup something at the client.