Is there a way to suppress or configure an equation within an assembly?

The functionality used to be there (right click the equation within the equation manager and as well as the delete equation option there used to be a "Suppress" and "Unsuppress" option for specific configurations). This functionality was removed in a previous version I believe and now there is an option within the equation manager at the end of the "=" side of the equation that lets you select configurations (its a drop down box which lets you "Specify Configurations")... except it doesn't seem to work for me.

Is anyone else able to get this to work or am I misinterpreting the functionality?

I have created a very simply assembly of 2 flat plates with an equation for the length of each flat plate (simply an =number to show the idea) and then I have created a 2 configurations to show each flat plate separately by suppressing the uneeded one in each configuration respectively. You will see in each of the configurations there is an equation manager error/warning and I am unable to specify the configurations for the equations as it says... "Cannot deselect the active configuration for this operation" when I try and unselect the configuration I don't want the equation to be active in????

Anyone else have this issue??