There is a "raw" method, which however also has as result that a longer title will continue at the right hand side (over or underneath what's already there).
The method is simply switching off the maximum length for a movie title as defined in the skin's ini-file:
(Exit BSPlayer before proceeding with what follows:)
E.g. : in subfolder "skins" within BSPlayer's installation folder you will find a folder "base" or "bsp2" which holds all files which together form that skin. There will also be a file "skin.ini" in that folder. Open that file with Notepad. Search for "MaxTitleWidth" (below "[Display]").
Place a semicolon at the beginning of that line, like this
; MaxTitleWidth=235
(There may be a different value of course).
Now exit and save the skin.ini -file
Start BSPlayer and play a movie with a long filename.
(For other skins you will have to unzip the .bsz skinfile first)