Hi Jesper,
If you activate the "ReadOnly" theme. ... RightSidebar: Tools: theme button: select "ReadOnly" ... you get a slightly modified UI. ...
The save button is also there. Just 4 buttons down.
That's not optimal but simple to achieve without any modifications. .... But be aware, that the tiddler menue: more dropdown still contains a delete button, which works and probably causes an "autosave" ...
So all in all ... as you found out... suboptimal :/
There
have been some discussions in the group, but imo there is no generic solution, which keeps a simple editors UI and possibilities, but prevents the user from accidentally changing something. .. At least I don't know it :)
-m