Thanks for your prompt answer.
For fullscreen it's strange, sometimes it works, sometimes not (using Firefox btw), yesterday evening I had to resize the window then the button would work.
Viewing post in Dicey Dungeons v0.10.1 (Bugfix update) comments
Oh, must be that v23 (current stable) bug about spaces in file names for HTML5 games.
I've been playing it in the v25 beta, works great there :)