This is not an issue as such. more an observation - possibly bug, I have updated my VCL UI pack. when I then compiled my application, "AdvRichEditorEmailIO" was no longer recognised, despite all other VCL UI units being OK including "AdvRichEditorToolBar". To Solve this, I had to go a import the "AdvRichEditorEmailIO.pas" separately into my project.
The component is not automatically registered for the tool palette.
The reason is the Indy dependency here. As this is sensitive to different Indy versions that might be used, delivering this precompiled against a specific Indy version is problematic with Delphi's compiler strict binary compatibility checks.
Therefore, we include the unit with source code that allows you to directly use it in code.