TRichView.com

TrvHtmlViewImporter imports HTML in TRichView, using THTMLViewer ( https://github.com/BerndGabriel/HtmlViewer/ )

Our installer installs TrvHtmlViewImporter automatically, if THTMLViewer 11.7 is already installed
(THTMLViewer does not include packages for Delphi 10.1 and 10.2; since the package for Delphi 10 is named FrameViewerXE9.dpk, our installer assumes that the package for Delphi 10.1 is FrameViewerXE10.dpk, and for 10.2 is FrameViewerXE11.dpk)

THTMLViewer 11.8 was released recently.
Unfortunately, it has changes that prevent compilation of TrvHtmlViewImporter, some properties of THtmlTable were made private.
I already sent a request to return them back, I hope this problem will be fixed.

Meanwhile, you have the following solutions:

1) Use version 11.7 (you can choose a version to download on their web site)
2) Use version 11.8 with modifications. Open HTMLSubs.pas, find the declaration of THtmlTable, and move from the private to the public section the following variables:
BkGnd, BkColor, CellSpacingVert, CellSpacingHorz, CellPadding.

Today, THTMLViewer 11.8 was updated, and now it is compatible with TRichView again.

How does the installer check if the htmlViewer is installed? I compiled THTMLViewer version 11.8 in delphi tokyo. I created the packages FrameViewerXE11.dpk and dclFrameViewerXE11.dpk. The installer says: Installing optional RvHtmlViewImporter... Skipped. So it doesn't detect the htmlViewer.

Open the package <TRichView Dir>\ThirdParty\rvHtmlViewImporter\Source\rvHtmlViewImportD10_2.dproj in Delphi IDE, compile it, post error messages here.

When I compile it manually, I don't get any error.

Strange, after completely uninstalling richView and reinstalling it, it does install the htmlViewImporter automatically.

As I understand from your email, the problem was in the "build control" package options.
For your HTML viewer packages, open "Project | Options", "Description", set "Build control" = "Explicit rebuild".
All our packages are "explicit rebuild" packages, including RvHtmlViewImporter package. And "explicit rebuild" packages cannot refer to "rebuild as needed" packages.