[MlMt] "Line Height Delta" doesn't seem to work anymore in Mojave

[Sam Hathaway]

Hi Benny,

I use a Line Height Delta of -4 on the mailbox/sources sidebar to cram 
more into the available vertical space.

I just upgraded to Mojave and it looks like this setting is now being 
ignored. I can set it to any value I like and the line spacing shows up 
as if it was set to zero.

I’m running MailMate “Version 1.12 (5523)”.

Any fix or advice? Thanks.
-sam