I noticed that when I was rearranging the layout of where everything is in Roblox Studio (like the toolbox and the output), I would get a weird error seeming to be related to Roact.
15:46:02.893 - Plugin_-1.Toolbox.Core.Consumers.ModalConsumer:37: setState cannot be called while a component is being reified or reconciled.
15:46:02.898 - This is the step where Roact constructs Roblox instances, and starting another
15:46:02.899 - render here would introduce bugs.
15:46:02.899 -
15:46:02.899 - Check the component "ModalConsumer" to see if setState is being called by:
15:46:02.900 - * a child Ref
15:46:02.901 - * a child Changed event
15:46:02.901 - * a child's render method
15:46:02.902 - Stack Begin
15:46:02.902 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 227 - method setState
15:46:02.903 - Script 'Plugin_-1.Toolbox.Core.Consumers.ModalConsumer', Line 37 - local callback
15:46:02.904 - Script 'Plugin_-1.Toolbox.Core.Util.createSignal', Line 60 - method fire
15:46:02.905 - Script 'Plugin_-1.Toolbox.Core.Util.ModalStatus', Line 67 - method onSearchOptionsToggled
15:46:02.905 - Script 'Plugin_-1.Toolbox.Core.Providers.ModalProvider', Line 31 - field onSearchOptionsToggled
15:46:02.906 - Script 'Plugin_-1.Toolbox.Core.Components.MainView.MainView', Line 242 - field render
15:46:02.907 - Script 'Plugin_-1.Toolbox.Core.Consumers.LocalizationConsumer', Line 22 - method render
15:46:02.908 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 343 - method _forceUpdate
15:46:02.909 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 311 - method _update
15:46:02.909 - Script 'Plugin_-1.Toolbox.Libs.Roact.Reconciler', Line 396 - field _reconcileInternal
15:46:02.910 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 355 - method _forceUpdate
15:46:02.911 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 311 - method _update
15:46:02.912 - Script 'Plugin_-1.Toolbox.Libs.Roact.Component', Line 245 - method setState
15:46:02.913 - Script 'Plugin_-1.Toolbox.Core.Components.MainView.MainView', Line 158 - method calculateRenderBounds
15:46:02.914 - Script 'Plugin_-1.Toolbox.Core.Components.MainView.MainView', Line 145
15:46:02.915 - Stack End
You can reproduce it by doing something like I did here.