STEPS TO REPRODUCE
1. Launch iClone 6
2. Navigate to Content Manager > Actor > Avatar > 01_G6 Character, apply Mason
3. Navigate to Content Manager > Animation > Motion, apply a random Motion
4. Launch Timeline, go to Motion track, right-click and select Modify, "Motion Modifier" panel will popup
5. Go to Exaggeration, set Upper to 150, press "Enter" on keyboard

ACTUAL RESULT
It causes iClone 6 to preview unexpectedly

EXPECTED RESULT
It only can change the parameter value in Motion Modifier panel now