TinyMCE does not allow you to set the first column as a heading like Atto does

See the instructions for TinyMCE v Atto in the Intro to Accessibility course: https://moodle.academy/mod/book/view.php?id=1071&chapterid=1124

Relevant information from the course is copied below to show the difference.

If TinyMCE allows columns to be set as headings we should enable this.

In TinyMCE:

TinyMCE only allows you to set the table headings in the rows, not the columns.

1. Place your cursor into the row you would like to set as a heading (usually row 1).
2. In the menu at the top of the editor click either:
   1. Table > Row > Row properties.
3. From the row type choose Header.

In Atto:

Atto allows you to set the table headings to be at the top of the columns, in the first row, or both. 

If you need to check this you can:

1. Place your cursor in the table.
2. Click the table icon in the text editor menu (you may need to expand the editor to see all the options).
3. Choose Edit table from the drop down list. 
4. Check whether 'Define headers on' is set to Columns, Rows or Both. 
5. If you change this setting save your changes.