It was brundlefly that showed me this in X3e. It has become a bit less intuitive in SPlat.
Look at the top right of the control bar. There is a section where there are vertically-written names.
One of them is "Events". There is a knobbly area to it's left. Right click on that and select
"Resize Event Inspector Module" and choose "Large".
Now go back and click on a MIDI event. You will see the values in the Event Inspector.
Select a bunch of MIDI notes, go to the Event Inspector and change Length to, say, 24.
All selected notes will become length 24.
Once you get the hang of the it, you can change the size to "Small" so it takes up less space.
You will need to memorize the abbreviations, though.
DO NOT SELECT "Close Event Inspector Module".
I just did and it disappeared and i cannot for the life of me figure out how to bring it back!!!