Closing visualizer tab results in websocket connection error

[tkoolen]

Whenever I close a visualizer tab, I now (since a little while actually) get

Error handling websocket connection:
WebSockets.WebSocketClosedError("ws|server respond to OPCODE_CLOSE 1001:Going Away")
Stacktrace:
 [1] try_yieldto(::typeof(Base.ensure_rescheduled), ::Base.RefValue{Task}) at ./event.jl:196
 [2] wait() at ./event.jl:255
 [3] wait(::Condition) at ./event.jl:46
 [4] wait(::Task) at ./task.jl:188
 [5] create_socket(::Dict{Any,Any}) at /home/twan/.julia/packages/WebIO/Rk8wc/src/providers/mux.jl:44
 [6] (::getfield(Mux, Symbol("##5#6")){getfield(Mux, Symbol("##28#29")){Array{SubString{String},1}},typeof(WebIO.create_socket)})(::Function, ::Dict{Any,Any}) at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:17
 [7] #1 at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:10 [inlined]
 [8] splitquery(::getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##5#6")){getfield(Mux, Symbol("##28#29")){Array{SubString{String},1}},typeof(WebIO.create_socket)},getfield(Mux, Symbol("##1#2")){typeof(Mux.wclose),getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##18#19")){getfield(Mux, Symbol("##22#23")){Symbol,Int64}},getfield(Mux, Symbol("##20#21")){String}}}}, ::Dict{Any,Any}) at /home/twan/.julia/packages/Mux/FeATY/src/basics.jl:34
 [9] #1 at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:10 [inlined]
 [10] wcatch(::getfield(Mux, Symbol("##1#2")){typeof(Mux.splitquery),getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##5#6")){getfield(Mux, Symbol("##28#29")){Array{SubString{String},1}},typeof(WebIO.create_socket)},getfield(Mux, Symbol("##1#2")){typeof(Mux.wclose),getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##18#19")){getfield(Mux, Symbol("##22#23")){Symbol,Int64}},getfield(Mux, Symbol("##20#21")){String}}}}}, ::Dict{Any,Any}) at /home/twan/.julia/packages/Mux/FeATY/src/websockets_integration.jl:12
 [11] todict at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:10 [inlined]
 [12] #3 at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:14 [inlined] (repeats 2 times)
 [13] (::getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##3#4")){getfield(Mux, Symbol("##3#4")){typeof(Mux.todict),typeof(Mux.wcatch)},typeof(Mux.splitquery)},getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##5#6")){getfield(Mux, Symbol("##28#29")){Array{SubString{String},1}},typeof(WebIO.create_socket)},getfield(Mux, Symbol("##1#2")){typeof(Mux.wclose),getfield(Mux, Symbol("##1#2")){getfield(Mux, Symbol("##18#19")){getfield(Mux, Symbol("##22#23")){Symbol,Int64}},getfield(Mux, Symbol("##20#21")){String}}}}})(::Tuple{HTTP.Messages.Request,WebSockets.WebSocket{Sockets.TCPSocket}}) at /home/twan/.julia/packages/Mux/FeATY/src/Mux.jl:10
 [14] (::getfield(Mux, Symbol("##9#10")){Mux.App})(::HTTP.Messages.Request, ::WebSockets.WebSocket{Sockets.TCPSocket}) at /home/twan/.julia/packages/Mux/FeATY/src/server.jl:49
 [15] upgrade(::getfield(Mux, Symbol("##9#10")){Mux.App}, ::HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}) at /home/twan/.julia/packages/WebSockets/pc4iW/src/HTTP.jl:201
 [16] (::getfield(WebSockets, Symbol("#_servercoroutine#11")){WebSockets.ServerWS})(::HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}) at /home/twan/.julia/packages/WebSockets/pc4iW/src/HTTP.jl:370
 [17] macro expansion at /home/twan/.julia/packages/HTTP/wY7Vc/src/Servers.jl:360 [inlined]
 [18] (::getfield(HTTP.Servers, Symbol("##13#14")){getfield(WebSockets, Symbol("#_servercoroutine#11")){WebSockets.ServerWS},HTTP.ConnectionPool.Transaction{Sockets.TCPSocket},HTTP.Streams.Stream{HTTP.Messages.Request,HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}})() at ./task.jl:259