Callbacks are always called twice?

[cpsievert]

Notice how updating takes longer the more you click https://github.com/plotly/dashR/blob/master/inst/tutorial/examples/htmlwidgets/plotly-crosstalk.R

[cpsievert]

This problem was specific to the crosstalk component which is now fixed https://github.com/plotly/dashCrosstalkComponent/commit/5e7ae1d8dd81997031755803c4cfdd28d2eb35d5

There is, however, still an issue with the server executing a callback twice, but it seems like this may be a fiery issue (see thomasp85/fiery#34 for a minimal example) -- would be great to have some insight from @thomasp85 on that issue before investigating further