TRichView.com

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 ...

1. As for RTF import:
External images are supported. These images are inserted when reading 'INCLUDEPICTURE' or 'IMPORT' RTF fields.
If the referred picture is local, it is loaded automatically. If it is on a remote location, you need to use OnImportPicture event (but, if you use RichViewActions ...

TRichView need a parent form for formatting. The form may be hidden.
The alternative is using TRVReportHelper component. It contains invisible TRichView inside (accessible as RichView property) that does not need a parent form. TRVReportHelper must be formatted using RVReportHelper.Init method ...

If you want to find the location of the control, you can use this function:

procedure FindControlLocation(var RVData: TCustomRVData; out ItemNo: Integer);
var
table: TRVTableItemInfo;
r,c: Integer;
begin
ItemNo := RVData.FindControlItemNo(TControl(Sender));
if ItemNo<0 then
begin
RVData ...

The simplest solution is selecting the control on clicking on it: process OnMouseDown of controls, and call RichViewEdit.SelectControl() in it.
See the example in viewtopic.php?t=157 (how to resize and drag&drop controls in the editor).

AutoComplete property for these combo boxes is False by default, intentionally.
Each time when autocomplete works, the font is applied, adding a new item to RVStyle.TextStyles (if there is no existing items with these properties).
While these items will be removed after the next call of ...

The demo uses a workaround,

const
WM_DESELECTCOMBO = WM_USER + 1;

In the form's interface section:

procedure WMDeselectCombo(var Msg: TMessage); message WM_DESELECTCOMBO;
procedure DeselectComboBoxes;

Implementation:

procedure TForm3.DeselectComboBoxes;
begin
cmbFontSize.SelLength := 0 ...

TCustomRichViewEdit has a method for processing Backspace:
procedure OnBackSpacePress(Ctrl: Boolean);
But this method is protected.
You can try to call it in this way:

type
TCustomRichViewEditHack = class (TCustomRichViewEdit)
end;
...
TCustomRichViewEditHack(RichViewEdit1.TopLevelEditor ...