Hi Mark,
Thank you for having a look! I managed to discover what was causing the issue and fix it.
It was the Kimili Flash plugin, which broke as a result of updating to 4.0.1. This somehow affected the CSS, causing the issues I saw.
I have now replaced the plugin and it’s all working as expected!
Hi everyone – I found a useful alternative:
https://ww.wp.xz.cn/plugins/tinymce-advanced/
This improves the functionality of the Text Editor, and importantly adds the ability to insert videos. This means SWFs can be embedded this way and it is working with 4.0.1.
The only frustrating thing is you will have to re-embed everything manually as far as I’m aware.
I’m in the same boat – fingers crossed for an update soon.
Glad I’m not the only one with the issue!