Unable to use variable for required expression

[mattias]

Using RM 5.1 on firmware version 2.3.5.152, I am unable to set up a required expression using variable as the capability:

Selecting "variable" takes me to a screen where I cannot proceed from:

I have two local variables already defined in the RM instance:

Am I missing something fundamental here in order to use one of the local variables as a required expression or have I stumbled across a bug?

[pseudonym]

From the RM 5.1 documentation:

NOTE: Almost any condition can be used to create a required expression. However, local variables should not be used in conditions used to create required expressions (they do not generate events, and thus the required expression will not be re-evaluated when it changes). Hub variables and Private Boolean will work without caveats.

[mattias]

@pseudonym

From the RM 5.1 documentation:

Lol. RTFM! Thanks for pointing me to the answer