Command bar button not shown when select a record

[sukie_y]

Hi everybody,

I'm trying to add a command bar button using Ribbon workbench.  I'm very confused since there's no good document to explain what the properties of display rule mean.

You can see that I create a very simple sample to add a button to Home area.

The button is associated with a command:

And the display rules is :

Now I got this:

But when I select the record '4-1' the button2 disappeared...

Question 1 : Why is the button not displayed?

Question 2: Could anybody tell me what the properties of the rule means ? I guess what I set means: ‘When the login user has Basic Read privilege of the the current entity(EntityName is blank), and the entity is displayed as a subgrid(SelectedEntity?), then the rule is True(Defualt value), otherwise False(InvertResult value, but why empty works?...)  

Anybody helps me ? THANK YOU!!!!!!

Best Regards,

- Justin

[sukie_y]

Can't believe nobody knows why ...

Everybody did customize ribbon, don't you 😭