Repeating Clipped Envelopes - editing question

Not sure quite how to ask this question other than give an example:

I record everything rather than using mouse. Let's say I record 4.5 measures of piano, and I want to repeat the first 4 bars (ie the last half measure was when my hand moved from my keyboard to the mouse to stop recording.). If I cut the "Envelope" (is this the correct term?) at the end of the fourth measure, I'd like to then click on the right edge of the box and drag to the right and have it loop the 4 measures over and over. But, no, it inserts that extra half measure each time. How do I avoid this?

Sam