ActionTextEditor.mcc is a MUI custom class that subclasses TextEditor.mcc.
Pressing Return with text in the gadget calls a hook you supply with
MUIA_ActionTextEditor_SubmitHook. Right Shift + Return inserts a newline
instead, the same as TextEditor.mcc.

It was written for AmigaGPT and is published so other MUI programs can use
the same Return-to-submit behaviour.

MCC_TextEditor 15.56 or later MUST be installed before this class will
load. Download it from:
https://aminet.net/dev/mui/MCC_TextEditor-15.56.lha

Requirements:
- MUI 3 or later
- MCC_TextEditor 15.56 or later installed
  (https://aminet.net/dev/mui/MCC_TextEditor-15.56.lha)
- AmigaOS 3.1+ with a 68020 or higher, AmigaOS 4.1, or MorphOS

Installation:
- Extract MCC_ActionTextEditor.lha
- Run Install-MCC_ActionTextEditor
- The installer copies ActionTextEditor.mcc to MUI:Libs/MUI on AmigaOS
  or SYS:Classes/MUI on MorphOS
- Reboot or restart MUI applications that should pick up the class

Developer:
- include/mui/ActionTextEditor_mcc.h is in the Developer drawer
- Autodocs/MCC_ActionTextEditor.doc is in Developer/Autodocs
- Class name: ActionTextEditor.mcc
- Attribute: MUIA_ActionTextEditor_SubmitHook

Source:
https://github.com/sacredbanana/MCC_ActionTextEditor

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-rw-r--r--   502/20        754    1612  46.8% -lh5- 82d6 Aug 30 00:22 MCC_ActionTextEditor/ActionTextEditor.readme
drwxr-xr-x   502/20          0       0 ****** -lhd- 0000 Aug 29 23:45 MCC_ActionTextEditor/Developer/
drwxr-xr-x   502/20          0       0 ****** -lhd- 0000 Aug 29 23:45 MCC_ActionTextEditor/Developer/Autodocs/
-rw-r--r--   502/20       2207    6870  32.1% -lh5- f445 Aug 30 02:51 MCC_ActionTextEditor/Developer/Autodocs/MCC_ActionTextEditor.doc
drwxr-xr-x   502/20          0       0 ****** -lhd- 0000 Aug 29 23:26 MCC_ActionTextEditor/Developer/include/
drwxr-xr-x   502/20          0       0 ****** -lhd- 0000 Aug 29 23:26 MCC_ActionTextEditor/Developer/include/mui/
-rw-r--r--   502/20        404     853  47.4% -lh5- ce12 Aug 30 02:51 MCC_ActionTextEditor/Developer/include/mui/ActionTextEditor_mcc.h
-rw-r--r--   502/20        966    2810  34.4% -lh5- 2ed1 Aug 29 23:26 MCC_ActionTextEditor/Install-MCC_ActionTextEditor
drwxr-xr-x   502/20          0       0 ****** -lhd- 0000 Aug 30 00:02 MCC_ActionTextEditor/MCC/
-rw-r--r--   502/20          0       0 100.0% -lh0- 0000 Aug 30 00:02 MCC_ActionTextEditor/MCC/.gitkeep
-rwxr-xr-x   502/20       4389    9216  47.6% -lh5- f7ae Aug 30 02:51 MCC_ActionTextEditor/MCC/ActionTextEditor_MorphOS.mcc
-rw-r--r--   502/20       2009    4240  47.4% -lh5- 0367 Aug 30 02:51 MCC_ActionTextEditor/MCC/ActionTextEditor_OS3.mcc
-rwxr-xr-x   502/20       4840   10876  44.5% -lh5- 4e24 Aug 30 02:51 MCC_ActionTextEditor/MCC/ActionTextEditor_OS4.mcc
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