It appears that when using the visual editor and submitting with either "save as draft" or "publish" doesn't save the actual article text.
This is because the textarea is display:none; visibility: hidden and invisible form elements don't get sent. (Instead of relying on the textarea, you could, for instance, copy the content with every keyup event to an <input type="hidden" /> which would definitely get sent with the submit.)
display:none; visibility: hidden
<input type="hidden" />
Also, when using the "preview" button, at least the text should be saved first, maybe by triggering the autosave before the preview window is opened.
Fixes autosave not saving the text when using visual editor.
Text was not saved because visual editor sends unified body_and_extended field. Adding a check in the content_controller did the trick.
Also fixes issue #91
This bug has been fixed in Typo 6.1.1. We encourage you to update your Typo version to the latest stable to profit from that fix.
As for the issue of clicking the Preview button, expecting the text to be saved before opening / reloading the preview window, is this a new issue?
@itsfriday Probably. Can you open a new GitHub issue for this problem, please?