HP49-50G : Black rectangle variable

[Wes Loewer]

You can use the Filer to rename a variable to blanks like ' ' which will show up in the VAR menu as a black rectangle.

Have you considered making a custom menu instead? You could store
{A1, {}, A3, A4, A5, A6, B1, B2, B3, B4, {} }
in CST and the custom menu would display blanks in place of the {} entries.