Sliderends get unsnapped after changing slider anchor type

[cihe13375]

1. create a linear slider
2. change the first anchor to perfect curve
3. now the sliderend is unsnapped

it also happens in the reverse way, i.e. create a perfect curve first and then change to linear.

I once thought this is a feature but decide to report it after seeing someone with 99999 sliderends unsnapped in the verify tab and I guess this is the most likely reason

output.mp4

[peppy]

#29915