I know the question has already been asked some ten years ago, version at the time was 6.x and there was no real answer.
I tried different settings in control panels and even trough the setup WYSIWYG wizard but I can't get a full WYSIWYG editor in forums.
In pages I have the WYSIWYG editor with the option to switch to source and back. In forums I have an editor like here with buttons generating syntax. There is an additional button on the right to "Switch editor (wiki or WYSIWYG)" but clicking it just sets me back to the forum topics list.
Is it possible to use a full WYSIWYG editor in forums and if it is, what settings are required? My Tiki version is 21.2.