Loads of problems with the editor

I am having huge difficulty with using my editor on my phbb3 forum. Coding disappears and sometimes lines shift or don't register for no reason whatsoever. For example, I could center one line and then post and it doesn't center, or I could center one line and all of them get centered. I have used this editor for years and don't normally have any problems.

I can also not see the WYSIWYG button at all...

SO whats going on??

Are you using Chrome?  Try a different browser.

Hello @PA,

Have you made any modifications recently ? As for content disappearing that is usually caused by formatting errors in your bbcode. You can however prevent auto-corrections from the editor by using the script in this tutorial.
https://help.forumotion.com/t135105-correct-the-formatting-of-the-new-editor-in-source-code-mode#909385

Oh, that may be it. I'll try that thanks.
I don't think so Ange.. Where can I edit the editor from? Mainly through javascript right? The only javascript I am using on the editor is to display the word count.

CSS, or JavaScript can make modifications.

You said the WYSIWYG button was missing, did you add a css rule with the following selector ?
Display > Colors > CSS stylesheet

Code:

.sceditor-button-source