st: Unexpected result from a marginsplot

[Jordan Silberman <silberman.stata@gmail.com>]

Hello,

I have an xtmelogit model with a highly significant time by condition
interaction. I used the margins command to estimate coefficients for
the effects of time separately for the 2 conditions (simple effects).
I then used marginsplot to plot rates of change for the 2 conditions
as a simple bar graph (with 2 bars, each representing a rate of change
for 1 of the 2 conditions). Here's the code:

margins, dydx(time) over(cond) predict(fixedonly)
marginsplot, recast(bar)

Given that the time X condition interaction is significant, I'd expect
the error bars on the 2 bars not to overlap (the rates of change
should significantly differ across groups). However, the two error
bars overlap. Any idea why this might be?

Thanks!
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