Fwd: Tabs are ready? -> Let us give a definition of tabs.

[Alin Soare]

... and what is a "standard event" in this context?  And why can a
toolbar button not react to such a standard event in the same way?

Initialize tab, hide tab, show tab, kill tab, at least.

I think it should be evident why toolbar or menub cannot do it: because there is no C code to call the events when needed.