Here is a list of things that is broken or not working in TinyMCE shipped with Plone 5.2:
BUG: a table can be visually resized but the width is always reset to 100%
BUG: cell width and height can be visually changed but width/height are always reset to their default
BUG: "Table properties" basically dysfunctional (e.g. setting a border has no effect)
USABILITY: 4 fours way to set text to bold/italic: toolbar, formats dropdown in toolbar, format menu, format -> formats-> inline menu
BUG: almost all styles from format dropdown/menu are not persisted
BUG: left|right|center|justify from toolbar visually working but not saved
BUG: indent|outdent from toolbar visually working but not saved
"Visual aids" not working
BUG: inserting "horizontal line" not working
insert media: you can not change the size of an inserted video other through editing the HTML source code
The issues affect the most basic functionality of TinyMCE. Obvious bugs and misbehavior that affects every content editor working with Plone. The current situation is a disgrace for any content editor (not mentioning (again) that we advertise Plone as "enterprise CMS" but ship it completely messy editor).
There is an urgent need for everyone for having the issues (marked as BUG) fixed in Plone 5.2 asap.
There is certainly a budget for fixing things in one of our current customer projects and there is perhaps some budget in your customer project.
I would like coordinate the work to be done here and asking for
a dev that has the knowledge and insight for fixing the issues marked as BUG
financial support from other Plone solution providers for getting TinyMCE fixed for our your and our customers and all Plone users
the best is adding tests that return errors. Developers hates red blinking around and will try to fix it.
But html formatting is quite impossible to reproduce, maybe robot tests can do it. Some test can just work adding html content to the field and saving it and doing a test checking what should not be filtered out.
I have posted some details on formatting issues but actually fixing them might be tricky.
One class of format issues is that they assign a "style" attribute which is stripped by TinyMCE by default. Reported with a proposal here https://github.com/plone/Products.CMFPlone/issues/3069. Plone is getting its list of good attributes from lxml.html.defs.safe_attrs + custom assigned attributes. "style" is not in that def. Is there a way to get it to do this by applying a tag/class or do we need to allow the style attribute?
Nice to have: there are several 3rd party options for styling tables such as the Datatables jQuery plugin. A lot of these rely on having <thead> and <th> tags. It is currently a huge PITA to change these through properties - you have to set the property on the row and on each cell. This might be a TinyMCE limitation but would be nice if you could set this on the table level.
To answer, if you need style, use the jquery .css() on the tag to set it.
There is is pull request on mockup from march 2019 to upgrade to TinyMCE 5.0.1 which seems not that invasive/large. Biggest issue wille be compatibility testing.
But the currently used TinyMCE 4.x hasn't been updated in mockup for a while either, we are using 4.7.13 from the https://github.com/artursmirnov/tinymce_builded repo, where tinymce itself is now at 4.9.10. @frapell and @erral have been doing most of the effort by updating the builded versions of tinymce in that repo.
I do realise a lot of the issues above are around html filtering, which updating TinyMCE itself might not solve. But it could save us from hunting down other obscure TinyMCE issues that have been fixed upstream if we stick closer to their releases/updates.
Disable html filtering
Revert 'disable filtering'
I remember having similar issues where the html filtering worked half ass-ed and this kind of trick worked. @mauritsvanrees looked at it and solved part of the issue, but I cannot find back the issue/ticket on github.
Those serve different purposes. The formats pullout is the set of table classes you can define in the control panel. It makes sense to me to have these Headers/Block/Tables/etc sections grouped together for defining the class(es) that these belong to. The table dropdown is properties specific to a table.
I am still in favor of @zopyx's point though. You can configure the entire toolbar in Plone already and my company does this to be less noisy, but it would be good to clean up a bit for Plone core.