@Mohamed Amin
That works as well, but as in all my previous tiddlers as tw5 wikitext, I was highlighting the blocks text and using the button in the editor to mark it as monotext. It was using ```block``` without problems. Since the result was showing a single backtick as part of the block and all the text below it, I had played with it and discovered `` would work.
When an editor starts displaying different formatting behavior using the defaults and no changes, that gets me nervous. Imagine if that occurred to you while writing up a peer review with it's strict formatting. It would be disturbing. It's like creating a HTML page displayed differently from previous HTML pages using the same browser.
It's not like scouring code for hours, spotting nothing, have a peer review it to discover a variable, function or class had a capitol letter instead of lower case. That has happened often enough to me it's embarrassing :-)