Read Only options for Interactive Grids (IG).

Dynamically setting Interactive Grids columns to Read Only (or Disabled) can cause some cell values to become null when submitting the IG.
In the examples below, I have tried to replicate this without actually saving the changed data - I would like my DEPT table to stay unchanged for other pages :-) Also I have used "1 = 1" as the "dynamic" part, but you get the idea.
I have added a Debug field to all the IGs, which are filled with the column values of all modified rows, during the Submit.
The DEPTNO and DNAME columns are all Read Only in the examples below, using various methods. The LOC column can be edited and "saved" by using the Submit button for that IG.

IG-1 and IG-2 are there for reference only. All columns are disabled by default so no Submit option there. The columns do look different from the other IGs however, which is a shame, but that can be fixed with some CSS if you like.
IG-3 and IG-4 work fine, but of course the columns are not dynamically set to Disabled or Read Only.
You can see the problem in IG-5 and IG-6. If you change the value of only 1 row, it works fine. But if you change the value of 2 or more rows, only the last row is OK - for the other rows, the Read Only columns have become null.
IG-7 fixes the problem by using some JavaScript. Too bad JavaScript is needed here, but what can you do...

Info & inspiration:

• https://dickdral.blogspot.com/2016/11/disabling-apex-items-right-way.html
• https://srihariravva.blogspot.com/2020/07/interactive-grid-conditional.html

Region

Identification
	Sequence	-949
	Title	IG-3 - Display Only columns
	Type	Interactive Grid
Source
	Source Type	NATIVE_IG
	Table Name	DEPT

Region

Identification
	Sequence	-939
	Title	IG-4 - Read Only columns
	Type	Interactive Grid
Source
	Source Type	NATIVE_IG
	Table Name	DEPT

Region

Identification
	Sequence	-929
	Title	IG-5 - DA "After Refresh (Region)" Disable columns
	Type	Interactive Grid
Source
	Source Type	NATIVE_IG
	Table Name	DEPT

Region

Identification
	Sequence	-919
	Title	IG-6 - DA "Row Initialization (IG)" Disable columns
	Type	Interactive Grid
Source
	Source Type	NATIVE_IG
	Table Name	DEPT

Region

Identification
	Sequence	-909
	Title	IG-7 - DA "Row Initialization (IG)" JavaScript
	Type	Interactive Grid
Source
	Source Type	NATIVE_IG
	Table Name	DEPT

Button

Name
	Button Name	RESET_PAGE
	Text Label / Alt	Reset Page
Displayed
	Sequence	10
	Display in Region	Reset Page

Button

Name
	Button Name	SUBMIT_IG_3
	Text Label / Alt	Submit IG-3
Displayed
	Sequence	10
	Display in Region	IG-3 - Display Only columns

Button

Name
	Button Name	SUBMIT_IG_4
	Text Label / Alt	Submit IG-4
Displayed
	Sequence	20
	Display in Region	IG-4 - Read Only columns

Button

Name
	Button Name	SUBMIT_IG_5
	Text Label / Alt	Submit IG-5
Displayed
	Sequence	30
	Display in Region	IG-5 - DA "After Refresh (Region)" Disable columns

Button

Name
	Button Name	SUBMIT_IG_6
	Text Label / Alt	Submit IG-6
Displayed
	Sequence	40
	Display in Region	IG-6 - DA "Row Initialization (IG)" Disable columns

Button

Name
	Button Name	SUBMIT_IG_7
	Text Label / Alt	Submit IG-7
Displayed
	Sequence	50
	Display in Region	IG-7 - DA "Row Initialization (IG)" JavaScript

Dynamic Action

Identification
	Name	IG-5 Disable columns
Execution Options
	Sequence	10
When
	Event	After Refresh
	Selection Type	Region
	Region	IG-5 - DA "After Refresh (Region)" Disable columns
Server-Side Condition
	Type	Expression
	Expression 1	1 = 1
	Expression 2	PLSQL
Advanced
	Event Scope	Static
True Action
Identification
	Action	Disable
Execution Options
	Sequence	10
	Fire On Initialization	Yes
Affected Elements
	Selection Type	Column
	Column(s)	DEPTNO,DNAME

Dynamic Action

Identification
	Name	IG-6 Disable columns
Execution Options
	Sequence	20
When
	Event	Row Initialization [Interactive Grid]
	Selection Type	Region
	Region	IG-6 - DA "Row Initialization (IG)" Disable columns
Server-Side Condition
	Type	Expression
	Expression 1	1 = 1
	Expression 2	PLSQL
Advanced
	Event Scope	Static
True Action
Identification
	Action	Disable
Execution Options
	Sequence	10
	Fire On Initialization	Yes
Affected Elements
	Selection Type	Column
	Column(s)	DEPTNO,DNAME

Dynamic Action

Identification
	Name	IG-7 Disable columns
Execution Options
	Sequence	30
When
	Event	Row Initialization [Interactive Grid]
	Selection Type	Region
	Region	IG-7 - DA "Row Initialization (IG)" JavaScript
Server-Side Condition
	Type	Expression
	Expression 1	1 = 1
	Expression 2	PLSQL
Advanced
	Event Scope	Static
True Action
Identification
	Action	Execute JavaScript Code
Settings
	Code	this.affectedElements .addClass('apex_disabled') .attr('tabindex','-1');
Execution Options
	Sequence	10
	Fire On Initialization	Yes
Affected Elements
	Selection Type	Column
	Column(s)	DEPTNO,DNAME

Process

Name
	Button Name	Clear all items
	Type	Clear Cache for all Items on Pages (PageID,PageID,PageID)
Process Point
	Sequence	10
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	1178

Process

Name
	Button Name	IG-3
	Type	PL/SQL anonymous block
Process Point
	Sequence	30
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	declare l_debug varchar2(4000) := :P1178_IG_3_DEBUG; begin l_debug := l_debug || 'DEPTNO=' || :DEPTNO || ' - '; l_debug := l_debug || 'DNAME=' || :DNAME || ' - '; l_debug := l_debug || 'LOC=' || :LOC || '<br/>'; apex_util.set_session_state(p_name => 'P1178_IG_3_DEBUG', p_value => l_debug); end;
Conditions
	When Button Pressed	SUBMIT_IG_3

Process

Name
	Button Name	IG-4
	Type	PL/SQL anonymous block
Process Point
	Sequence	40
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	declare l_debug varchar2(4000) := :P1178_IG_4_DEBUG; begin l_debug := l_debug || 'DEPTNO=' || :DEPTNO || ' - '; l_debug := l_debug || 'DNAME=' || :DNAME || ' - '; l_debug := l_debug || 'LOC=' || :LOC || '<br/>'; apex_util.set_session_state(p_name => 'P1178_IG_4_DEBUG', p_value => l_debug); end;
Conditions
	When Button Pressed	SUBMIT_IG_4

Process

Name
	Button Name	IG-5
	Type	PL/SQL anonymous block
Process Point
	Sequence	50
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	declare l_debug varchar2(4000) := :P1178_IG_5_DEBUG; begin l_debug := l_debug || 'DEPTNO=' || :DEPTNO || ' - '; l_debug := l_debug || 'DNAME=' || :DNAME || ' - '; l_debug := l_debug || 'LOC=' || :LOC || '<br/>'; apex_util.set_session_state(p_name => 'P1178_IG_5_DEBUG', p_value => l_debug); end;
Conditions
	When Button Pressed	SUBMIT_IG_5

Process

Name
	Button Name	IG-6
	Type	PL/SQL anonymous block
Process Point
	Sequence	60
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	declare l_debug varchar2(4000) := :P1178_IG_6_DEBUG; begin l_debug := l_debug || 'DEPTNO=' || :DEPTNO || ' - '; l_debug := l_debug || 'DNAME=' || :DNAME || ' - '; l_debug := l_debug || 'LOC=' || :LOC || '<br/>'; apex_util.set_session_state(p_name => 'P1178_IG_6_DEBUG', p_value => l_debug); end;
Conditions
	When Button Pressed	SUBMIT_IG_6

Process

Name
	Button Name	IG-7
	Type	PL/SQL anonymous block
Process Point
	Sequence	70
	Process Point	On Submit - After Computations and Validations
	Run Process	Once Per Page Visit (default)
Source
	Process	declare l_debug varchar2(4000) := :P1178_IG_7_DEBUG; begin l_debug := l_debug || 'DEPTNO=' || :DEPTNO || ' - '; l_debug := l_debug || 'DNAME=' || :DNAME || ' - '; l_debug := l_debug || 'LOC=' || :LOC || '<br/>'; apex_util.set_session_state(p_name => 'P1178_IG_7_DEBUG', p_value => l_debug); end;
Conditions
	When Button Pressed	SUBMIT_IG_7