TRichView.com

It looks like this is a bug.
Open fmxRVSelectionHandlesFM.pas, and change procedure TRVFMXSelectionHandles.Clear to:

procedure TRVFMXSelectionHandles.Clear;
begin
FLeftSelPt := nil;
FRightSelPt := nil;
FCaretPt := nil;
end;

Then recompile the packages (run "Install TRichView FMX in Delphi IDE ...

This exception happens in try..except block, and finally LoadRTF function simply returns False.
The exception is not noticeable unless debugging in Delhi IDE.

The correct way to change zooming is assigning DocumentPixelsPerInch property (in VCL and Lazarus versions)

The values in this table are indexes of initial styles. These styles are added to TRVStyle.TextStyles by default, but you can add and delete them.

While editing (including insertion from a file or the clipboard), new styles can be added. Editing operation do not delete styles, but they can add new ...

I also noticed that your using of the \u# for unicode chars does not have the fallback char in it, like "\u123456 ?". I thought that fallback char was mandatory.
Fallback chars are optional. If you need them, include rvrtfDuplicateUnicode in RTFOptions property.
These characters are useful if this ...

This is a TRichView bug.
It appears that SimpleConcateSubitems processes each item in table cells twice (when calling MassSimpleConcate, and directly in SimpleConcateSubitems). As a result, the number of calls grows exponentially depending on the table nesting level.
When table nesting level is not ...

TRichView uses format strings with "%s" placeholders for list text (RVStyles.ListStyles[].Levels[].FormatString).
However, it is expected that "%s" placeholders are used only in FormatStrings for numbered list types (like decimal, Roman, etc.), not for bullets.
So, for bullets, TRichView saves ...

OnClick means clicking on control, and TRichView has the default behavior inherited from TControl.
I suggest using other mouse events instead.

Yes, the idea is generally correct.

Some notes:

1. Your code does not work if the hyperlink is in a table cell.
(the "current" methods work for cells, but not methods that use item indexes)
To fix, instead of RichViewEdit1, use RichViewEdit1.TopLevelEditor.

2. When finding a range of the link's ...

Yes, if a hyperlink has text having different fonts, it is represented as several text items.
But they are highlighted as a whole, and they are saved back to RTF as a single hyperlink.

However, if you want to update the link target, you need to update Tags of all adjacent items that has the same ...

What's your code in OnDrawStyleText?

Answered in a private message.

\leveltext\'02·\'00 defines a two-character string. The first character is '·', the second character is a placeholder for the list counter.
However, for this list, \levelnfc23 is set, that means "Bullet" (no list counter).
While this is bug of this RTF, I'll change RTF reading code to remove list ...

Do you want to do it as an editing operation (undoable?)
If yes, just select the link and insert a new content. The selection will be replaced.

Let the caret is in the item that needs to be replaced, and the new RTF content is in Stream:

var
ItemNo, Offs1, Offs2: Integer;
rve ...

Unfortunately, this functionality is not supported. As far as I know, TComboBox does not provide notification when an item is highlighted without selecting it.

PS: AutoComplete does not work properly, because after the first completion, the combobox moves the input focus to the editor. It will be ...