If you apply a class filed in TW 5.1.19 and before you get the CSS applied to tc-tiddler-frame In Tw 5.1.20pre it seems it has been changed!
Make below experiment in two TW as below
class: MistyRose
created: 20190708151308705
modified: 20190708151930578
tags: $:/tags/Stylesheet
title: New Tiddler
<style>
.MistyRose{background-color:#FFE4E1;}
</style>
! Test
Hi Mohammad
!! TW <<version>>
A tiddler to do the experiment is attached!
You got these different results
--
You received this message because you are subscribed to the Google Groups
"TiddlyWiki" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/tiddlywiki.
To view this discussion on the web visit
https://groups.google.com/d/msgid/tiddlywiki/1de857d3-7854-4a7b-a7b9-397ee6e62942%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
New Tiddler.tid
Description: Binary data
