When I created some segments to play with the other day, I noticed that all effects had ~1 second flash to them (091).
Doing some more testing today (010), I found that if I select Segment 0 and choose ColorLoop, it’s smooth (no flashing). If I select Segment 0 and 1, they are both smooth.
Ideas? More testing data?
Hi, make sure the segments don’t overlap. Flashing typically happens if multiple segments try to draw to the same LEDs. Most effects now use a shared refresh rate so this issue will be less obvious, Solid is the most notable exception. My recommendation is to set the stop LED of Segment 0 and then create Segment 1, which will fill the rest of the LEDs 
Interesting. Set the Stop of Segment 0 to what?
UPDATE!
I made Seg 0 0-1 and then Seg 2: 1-11.
All good! TY!
Even better: For some reason, I thought Segment 0 was special and had to be the whole strip. Not!
You are not the first 
DrZzs also thought so on his first stream about 0.9. Probably because people usually count from 1 but programmers don’t 
Next hurdle: How can 0-1 and 1-2 not overlap. 
Another thing not really intuitive for us mere mortals The stop led is not included in the range. This is so that you can do stop - start to get the segment length. So 0-1 is actually only the first LED. In hindsight I should have implemented this differently, but I wanted the API and the frontend to align as to not cause confusion. It still does 
I updated the wiki. 