I just edited my road on https://www.beeminder.com/drtall/goals/gmailzero and ended up with a strange rendering: Dropbox - Screenshot 2015-07-21 10.24.46.png - Simplify your life
From July 21-28 the YBR isn’t shown on the graph! The critical edge is barely displayed, but the rest of the road is hidden. Not a huge deal but it looks kinda funny. 
Looks like an implied ymin of zero.
Your YBR goes negative (sloped at –1, then flat for a week or so, then at +3) before resurfacing.
Yeah. That seems kind of strange considering that the only way to get the critical edge on 0 is to have a negative valued YBR.
There have been other threads that wish for Beeminder to infer ‘right settings’ from the goal. This is an excellent counter-example, where it looks like something (beebrain, @dreev?) is arguably sensibly noting that gmailzero datapoints can’t go below zero and making a magical behind-the-scenes decision about how the graph should display or behave. Magic is hard to get right.
No magic in this case. We actually compute the plot range based on the datapoints and the beginning and end of the yellow brick road. If the road does something crazy in between, we let it go outside the plot range. Sometimes that looks buggy but other times it’s the lesser evil. I hope the long-promised Road Editor will change the tradeoff and we’ll want to make the plot range always include the whole road.
Of course! I see this all the time in the top end of some of my graphs; the uppermost datapoints get cut off because the plot range is based on the aggregated datapoints.
