Double redraws for brush

[jcheng5]

I'm seeing this with 108-module-output. After brushing one of the plots, you get two redraws, not one. It looks like the restoring of the brush sends very slightly different coordinates. Probably we should use not quite so many significant digits...

RECV {"method":"update","data":{"scatters-brush":{"xmin":15.654357184498,"xmax":21.369862814924,"ymin":22.591599977322,"ymax":30.113859997532,"coords_css":{"xmin":177.5500030517578,"xmax":280.5500030517578,"ymin":164,"ymax":241},"coords_img":{"xmin":253.00874588251108,"xmax":399.7837409710884,"ymin":233.69999217987075,"ymax":343.4249885082247},"img_css_ratio":{"x":1.4249999523162846,"y":1.424999952316285},"mapping":{"colour":"selected_","x":"cty","y":"hwy"},"domain":{"left":7.7,"right":36.3,"bottom":10.4,"top":45.6},"range":{"left":48.7397254003237,"right":783.191781083199,"bottom":521.260274599676,"top":7.80821891680156},"log":{"x":null,"y":null},"direction":"xy","brushId":"scatters-brush","outputId":"scatters-plot1"}}}

RECV {"method":"update","data":{"scatters-brush":{"xmin":15.654357184501,"xmax":21.369862814926,"ymin":22.591599977322,"ymax":30.113859997532,"coords_css":{"xmin":177.5500030518,"xmax":280.5500030518,"ymin":164,"ymax":241},"coords_img":{"xmin":253.0087458825712,"xmax":399.7837409711485,"ymin":233.69999217987075,"ymax":343.4249885082247},"img_css_ratio":{"x":1.4249999523162846,"y":1.424999952316285},"mapping":{"colour":"selected_","x":"cty","y":"hwy"},"domain":{"left":7.7,"right":36.3,"bottom":10.4,"top":45.6},"range":{"left":48.7397254003237,"right":783.191781083199,"bottom":521.260274599676,"top":7.80821891680156},"log":{"x":null,"y":null},"direction":"xy","brushId":"scatters-brush","outputId":"scatters-plot1"}}}

[jcheng5]

Observed on RStudio 1.2, Windows 10, R 3.5.2, with Chrome and Edge.

[dvg-p4]

Currently working on a pull request that will solve this and other brush-related issues at https://github.com/dvg-p4/shiny