Math mode simple does not work and deletes anything between your dollar signs.

Можно использовать не во всех полях текстового ввода, но строго в определенных. В моем случае я получил "The selected field is not valid for Markdown rendering. Please use a rich editor". Mozilla Firefox 89.0b7 (64-bit).

Working well for me so far in Gmail

This add-on is quite simply, brilliant. It lets you write Markdown in any text field that supports HTML/RTF.

I had been looking for a way to to work in Rally with Markdown and this was by far the easier option.

CTRL + ALT + M is now my favourite keyboard shortcut! Tables in Gmail are now easy!

Works great in GMail too.

This is a sweet addon... helping markdown the email at the click of a button :)

wish it could do markdown on the fly or not lose changes if you add on markdown after initially rendered. works well though!