Stefan,
For you to say the following "TiddlyDesktop is running maximized in Firefox" suggests you are using TiddlyDesktop to "host a node server" otherwise I don't understand the sentence.
- If the wiki is used in TiddlyDesktop, the full screen is effectively "disabled" because it is already "full screen within the application window".
- if the wiki is used in the browser full screen works because this is function of the browser, to hide the "chrome" (menus and application controls)
In item 1 Above, other than an inactive button, what would you like to happen? Remembering that you can maximise the application!
In TiddlyDesktop, I can also open a tiddler in a "new window" and maximise that, in the browser it carries a little more "chrome".
Regards
Tones