I just did a fresh install of WP (to make sure I wasn’t losing my mind) and I installed the latest version of Microthemer and it’s not working at all. Not working meaning that it doesn’t save to active-styles.css or if it does it’s not all of the changes.
I’m on a vanilla install with the TwentySixteen theme active and zero other plugins active.
Thanks for reporting this. I set up a fresh install with WP 4.5.2 Twenty Sixteen active. I wasn’t able to replicate the error you found unfortunately. I have actually been working on issue reported by another customer whereby setting !important manually sometimes doesn’t save. I haven’t been able to replicate the issue reliably on his site or my testing sever though. So I’m still not sure where exactly to focus my debugging efforts.
Is your vanilla install online? If so, would you mind sending me login details via this secure contact form?