Order-dependent failure to execute handler

[BioTurboNick]

I need to investigate further, but I'm observing that if I add a work-heavy handler to an Observable, subsequent handlers for the same Observable may never run.

[BioTurboNick]

I haven't resolved the ordering part, but the root problem was that exceptions thrown are being swallowed and not printed. There's a try/catch handler here that I think might be involved. I'll move this over to Gtk.jl though.

 [18] g_siginterruptible(f::Gtk.GLib.var"#90#92"{Ptr{Gtk.GLib.GValue}, UInt32, Ptr{Gtk.GLib.GValue}, Vector{Any}, Bool, GtkObservables.var"#33#34", Ptr{Any}}, cb::Any)