Bristol_Jonesey
Don't know what you mean by 'hanging'
It's a non-technical, non-explicit term hence I used apostrophes to indicate this; I was trying to indicate a problematic condition for which no precise term exists.
Splitting a MIDI clip across notes creates a situation where the length of the notes effectively extends beyond the boundaries of the clip, i.e. it's 'hanging over the edge' hence 'hanging'. The way Sonar handles MIDI notes is that they (should) exist within the boundaries of a clip, i.e. the software expects this to be the case; use the inline editor to draw a MIDI note in a track and Sonar will create a clip whose boundaries are the start and end of the note.
Splitting a clip across MIDI notes creates a situation which the Sonar software is not coded to handle, hence its very strange behaviour when subsequently manipulating the clip. Some DAW software handles this situation correctly, for example Logic, which will ask you whether you wish to keep, shorten, or split the notes.
The fact that Sonar does not ask this question is indicative of a problem in its implementation. This is pretty fundamental stuff. The fact that you and subalearts gave different answers to how Sonar manages the situation illustrates that this is a somewhat grey area that people are not very aware of.