Weird thing happened to me this morning. I have recorded a midi clip and tried to shrink it by clicking and dragging from the end of the clip. However the 'I' cursor does not appear to allow shrinking. If I go to the start of the midi clip the 'I' appears and I can shrink from the beginning. 
 
I realise that I must have a caught a shortcut key at some point but for the life of me I cannot work out which one. Any pointers would be most welcomed.
 
Thanks in advance

Have you tried switch tools ? Try using something other than the smart tool.
 

Thanks Chuck, if I swap to edit tools (F8 on keyboard) the slip editing facility works but not when smart tool is. Maybe smart tool isn't so smart. 
 

ya sounds like something is up with the smart tool. That why I suggest another tool (to narrow down the potential issue).
I've been doing a lot of Slip editing with midi clips lately (audio as well) and I haven't had any issues myself. 
But I have heard a few others say the fade and slip edit cursor/able to target the hit-zones has been difficult.
So your not totally alone in this. I just haven't noticed it.

Completely weird thing this morning, booted Sonar up and it's back to normal. I do note however that the hotspot for slip editing midi clips is lower down on the clip, but that may just be my imagination.

There were improvements done on clip editing in this months update.
Maybe the hit zones were tweaked.