Currently Sclender targets windows by concatenating the Window Title Prefix, Window Title Suffix, and Program Title fields, and looking for that combined string of letters in the title of the window you're currently using. If the text matches, Sclender targets it.
Splitting the match title into 3 parts is particularly useful when targeting Sclender at web browsers. For example say you are attaching Sclender to Microsoft Edge and want to target a game running on Facebook, you'd input the following (quotes excluded, and pay close attention to the spacing inside of them):
Window Title Prefix: "[Game title]"
Window Title Suffix: " | Facebook"
Program Title: " - Microsoft Edge"