For example - I have two videos or images in a row (done this already, which is why I'm asking stuff). If cue 1 has a fade in/out of two seconds and cue two has the same, I wind up with a two second crossfade - regardless of "Transition to next file" (I'mma call them TTNF for speed) settings. That's all fine. Also noticed that numbers sometimes mean things -- If [1] fades out over 2 seconds and [2] fades in over 10 seconds, there is the start of a crossfade, [1] "shuts" and [2] continues to fade in. So to keep those smooth, the numbers should (logically for the most part) match. BUT AGAIN, the exact same behavior no matter what the TTNF settings are.
If fade in/out info is included or not, on video or images - and TTFN is set to "Cross fade" -- Nothing. No cross fade.
Can't find clarity here and I'm just wondering if I'm missing something.

[EDIT] May have partially answered my own question, but now even more confused.
Tool tip came up while experimenting -- "Between this file and next file in the slideshow" -- Fair enough, I wasn't using a slideshow.
So I made one. And even though I put "cross fade" (various lengths) in the transition, no cross fades. Just cuts to the next.
SO - is that transition only used for slideshows (but shows up on anything)? And if so, does it not work in slideshows yet?