[TxMt] Make only _some_ invisibles visible?

[porneL]

I'd like to have non-breaking space* rendered in a visible way, but having  
tabs and line breaks remain invisible.

I've somewhat achieved that by adding new rule to the language bundle and  
setting background color for that scope, but it gives big block and I'd  
like to have a dot instead. Is there any rule in language bundles that can  
visually replace one character with another, or can I change list of shown  
invisibles?


* known as  , but I'm talking about the actual character, not entity.
-- 
regards, porneL