Adjusting loop length

Here's how:

1. Hover over the top right corner of the looped region to show the loop handle
   
2. Drag loop handle to the left to make the loop shorter. Dragging to the right will extend the loop and create more shadow (duplicate) regions
   

To adjust the length of the base region:

1. Use the handle in the lower right corner of the region
   
2. Click and drag to the left to make it shorter, or drag to the right to extend the loop up to its full length
   

You might want to zoom in, change the grid size, or turn off snap to grid mode in order to make finer adjustments. When you're happy with the length, you can use the loop handle again and drag it to the right to loop the region.

Pro tip: You can jump straight to the region handle of your base segment and drag to the left while the total number of loops/repetitions will stay the same!