When using a global number in a child component, the value is 0 (I used $bi(level)$).
It is correct when editing the formula, but is 0 when you are in globals list.
Also when creating a global number and don't set a value, the value is nothing. When used in a formula, it dhows the calculation with an empty string where the unset value must be.
When I set a color function to a global color, the child component can't inherit the parents color. This is a long time issue. Probably related to these issues: