I have used extensively another control, which can be programmed via the class CL_GUI_RTF_EDITOR
(it was used by the "SAPscript text editor", before SAP switched to Microsoft Word).
I can't tell you whether this RTF editor is less or more buggy than "your" BTF editor (CL_GUI_BTFEDITOR if it's the class you are talking about), because I don't know this BTF class.
But I can tell you that CL_GUI_RTF_EDITOR
has a weird behavior for some of its features. No idea concerning the performance. Note that it took me some time to understand how it worked, what were the limitations, and how to countervene them.
If you want to test the performance of the RTF editor, here is a very short example you may adapt :
DATA editor_id TYPE i.
DATA ed TYPE REF TO cl_gui_rtf_editor.
PARAMETERS dummy TYPE flag.
at SELECTION-screen output.
CREATE OBJECT ed
EXPORTING
parent = cl_gui_container=>screen0
EXCEPTIONS
OTHERS = 4.
CALL METHOD ed->create_editor
EXPORTING
LEFT = 1
top = 1
height = 500
WIDTH = 600
ascii_text = 'X'
CHANGING
editor_id = editor_id
EXCEPTIONS
OTHERS = 5 .
CALL METHOD ed->create_field
EXPORTING
p_name = 'HUGO'
p_value = 'mon texte'
p_width = 2000.
By the way, maybe another solution is to reuse a classic HTML text editor and embed it into a web browser (CL_GUI_HTML_VIEWER
class). The web browser is one provided by Microsoft, so maybe it's better designed.