TRichView.com

Yes, document should be reformatted after changing "show special characters" mode. Showing/hiding spaces and paragraph marks does require reformatting, but showing/hiding some Unicode characters (such as soft hyphens) requires reformatting.

Call RichViewEdit.Reformat.

Sorry, I am not sure that I understand the question.
1) What code is in this button's OnClick
2) Please give me examples of document text:
a) text what you want
b) text what appears

This problem was easy to fix. In CRVData.pas, in TCustomRVData.SaveRTFToStream, the following code
if (Level=0) and (StartItem<>EndItem) and
IsParaStart(EndItem) and (GetItemStyle(EndItem)>=0) and
(Items[EndItem]='') then
RVFWrite(Stream, '\par');
was changed to:
if (Level=0) then
RVFWrite ...

Format does not store the caret position, because Format is usually called when document is not formatted, so the caret position is undefined before its call.
If document is already formatted, why do you can Format?

please send me a screenshot and the stored report file

Use RVGetTextRange(rv, 0, RVGetTextLength(rv)) from RVLinear.pas

Did you mention other problems, except for the ending \par?

What version of TRichView and Delphi?

Please compile the demo with stack frames and without optimization (Compiler tab in the project options).
Run the demo. Which line of TRichView (or the demo (probably the problem is in event)) code generates the error?

Increase RVMaxAnimations variable from RVAnimate unit.

Notes:
1) Number of animated images were limited to save system resources.
2) In the latest version (available for registered users), resource and memory usage for animations (using TGifImage) was reduced dramatically. Now animated TGifImage ...

No, '\par' is fixed only in v1.9.27.2 (this is alpha version available for registered users).
By the way, why this ending \par is so important? The most if RTF readers do not require it.

First, why controls are not ok?
Instead of controls, you can use images. For example, hypertext images ("hot-picture" or "hotspot")

InsertControl inserts control in the position of caret. For hypertext pictures, use InsertHotPicture or InsertHotspot.
TRichView does not have caret, so (of course) it ...

Sorry, I am not sure that I understand your questions.
First, what do you mean by " the text is drawn as a graphics rather than a pure text"?

I do not understand why the results are different in TFileStream and TMemoryStream. It should not happen.

Answering questions here is a part of my work. Others may do it as a hobby :)
In this forum ("Examples, Demos") only I can create a new topic.
Other users can post their examples, demos, help and tips in "Support" forum. If they are interesting for other users, I'll repost them here.

const Indent = 24;
begin
RVStyle1.ListStyles.Clear;
// adding ListStyle[0] with 4 levels
with RVStyle1.ListStyles.Add do begin
with Levels.Add do begin
ListType := rvlstUpperAlpha;
FormatString := '%0:s.';
LeftIndent := Indent*1;
MarkerIndent := Indent*0;
FirstIndent := 0;
Font.Assign ...