I am using SlickEdit v18 beta 6 x64 and I just noticed a small cosmetic issue. The issue has persisted since at least v18.b4.
If you create a file with the filename "æøå.page", the main title bar correctly displays the name of the file but the file pane title (for the document) displays some bizarre UTF-8 encoded characters.
I regularly edit documents with foreign (i.e. Danish) national characters in them.
The problem does not seem to affect loading and saving the document, it is only a cosmetic issue as far as I can tell.
Please see the rather ugly red arrow on the attached image to see the problem.