Problem adding custom field to Activity subpanel

Both in my Calls module and Tasks module I have created a custom field that I would like to show in the Activities subpanel. Both custom fields show some kind of a subject, however the names of the fields are different. I would like to show the custom subject fields in the same column in the Activities subpanel, if this is possible.

I’ve made some changes in the ForActivities.php files, the first part of the list_fields array for the Call module looks as follows:

'list_fields' => array(
		'object_image'=>array(
			'vname' => 'LBL_OBJECT_IMAGE',
			'widget_class' => 'SubPanelIcon',
 		 	'width' => '2%',
		),
		'title_sub_c'=>array(
			 'force_blank' => true,
			 'force_exists' => true,
			 'vname' => 'Subject',
			 'force_default' => '(SELECT title_sub_c FROM calls_cstm WHERE calls_cstm.id_c=calls.id) AS',
			 'widget_class' => 'SubPanelDetailViewLink',
			 'width' => '20%',
		),
		'name'=>array(
			 'vname' => 'Details',
			 'widget_class' => 'SubPanelDetailViewLink',
			 'width' => '20%',
		),
                
               ...

And for the Task module:

'list_fields' => array(
		'object_image'=>array(
			'vname' => 'LBL_OBJECT_IMAGE',
			'widget_class' => 'SubPanelIcon',
 		 	'width' => '2%',
		),
		'subject_type_c'=>array(
			 'force_blank' => true,
			 'force_exists' => true,
			 'vname' => 'Subject',
			 'force_default' => '(SELECT subject_type_c FROM tasks_cstm WHERE tasks_cstm.id_c=tasks.id) AS',
			 'widget_class' => 'SubPanelDetailViewLink',
			 'width' => '20%',
		),
		'name'=>array(
			 'vname' => 'Details',
			 'widget_class' => 'SubPanelDetailViewLink',
			 'width' => '20%',
		),

                ...

The problem is that only the ‘subject_type_c’ field for the Task Module is shown in the Activity subpanel. The ‘title_sub_c’ field from the Call module shows up blank.The strange thing is that if I change the name ‘subject_type_c’ in the 2nd piece of code to ‘title_sub_c’ the Subject fields for the Call modules are shown in the Activity subpanel while the ones for the Task Module are shown as blanks.

I find the whole setup of the Activity panel a bit confusing and I’m not entirely sure if I use the ‘force_blank’ and ‘force_exists’ options correctly, as I’m not entirely sure what they mean.
Also my understanding of the ForActivities.php files is that the order of the list_fields array represents the column order, and not the names of the list_fields objects, but I might be wrong here?

So basically what I want is to show the ‘title_sub_c’ field from the Call module and the ‘subject_type_c’ field from the Task module in the same column in the Activity subpanel (for the Meeting module it can just show a blank). Am I missing something in my example codings?

Looks like I found a solution for this. I’ve renamed my list_fields ‘title_sub_c’ and ‘subject_type_c’ in my Call and Task module respectively to the same name ‘subject_c’ and defined the ‘subject_c’ field in the vardefs for Call and Task, as pointed out at the end of this article: https://developer.sugarcrm.com/2012/10/