The PluginGui:BindToClose documentation incorrectly claims that binding a function overrides the default closing behavior and that the developer must manually set PluginGui.Enabled to false to close the widget when a closing function is bound.
However, PluginGui:BindToClose does not prevent the widget from closing. Instead, it calls the bound function if present, then sets PluginGui.Enabled to false regardless of whether a closing function was bound.
A Roblox staff member stated in a post that this is the intended behavior.
Page URL: https://create.roblox.com/docs/en-us/reference/engine/classes/PluginGui#BindToClose