Why does the MIDI data in my MIDI event move when I try to resize it?

When I try to change the start or end point of the MIDI event in the project window, the data inside of it moves with it.

The Select (arrow) Tool has 3 different modes for what to do when resizing. You want to set it to normal. Not at DAW, but either right+click on it or maybe long+click (or…?) to change. Actual steps are in the manual.