I found H9 is a little different from h8 or before:

When I select the node A, whatever its display flag is on or not ,it displays the content of this node. I want it works as h8, only display the content of the node with display flag on, how to do it?

RMB on the Geometry Select Mode toggle (second button down from the top at the left of the viewer), and choose “Show Display Operator”.

I highly recommend setting in the Preferences so you don't ever have to change it again.

Edit > Preferences > Objects and Geometry > Default Geometry Display

Cheers!
steven

but please note that some tools will NOT work correctly when in Show Display Operator mode…paint capture layer being for one.

oh… thank you guys…this problem confused me for a long time…..