Hi Shiv Kumar,

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Inline Edit in your ListView may not work properly for some reasons. For example, incorrect permissions or Organization configurations. You can ensure the editor works by first checking the below items. 

Before you look any further, have your System Administrator check to see that you have the appropriate User Permissions. You'll need to have the following:
 
Both the "Enable Inline Editing" and "Enable Enhanced Lists" preferences turned on (Click Setup |Customize | User Interface)
Sharing Permissions necessary to edit the records in the list.
Permissions to edit the fields displayed in the list (note that inline editing enforces all page layout properties, such as marking fields "read-only" or "hidden").
Resolution
Configure your Organization for Inline Editor
 
Review the following Organization-specific settings: 
 
If your organization uses Record Types, you must include a Record Type Filter for a single record type in the List View criteria. Inline editing only works on lists that are filtered on a single record type. 
 
For example: "Record Type EQUALS Business Account", or "Record Type EQUALS <blank>" for records that don't have a record type. 
 
Inline Editing from a list will not work if there are any "OR" filters in conjunction with a record type filter (All list filters must be joined by an "AND" logic).
Also, Record Type cannot be edited for Case Object even if you have your list view filtered only on Single Record type.
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Good to know: Just having one Record Type in displayed records will not enable Inline Editing. You must identify a single record type in the List View criteria. If you don't have permission to edit the list criteria, contact your System Administrator.
 
If you are attempting to inline edit tasks or events, you must include a filter in the list criteria that restricts the list to displaying either tasks or events, not both. Include a filter of "Task EQUALS True" to edit tasks, or "Task EQUALS False" to edit events. If you do not have permission to edit the list criteria, contact your System Administrator.
If your organization uses Person Accounts (also known as B2C in some organizations), you must include a filter in Account list views of "Person Account EQUALS True" to edit Person Accounts. Likewise, use a filter of "Person Account EQUALS False" to edit non-Person Accounts. Note that Person Accounts are not inline editable from Contact list views.
Full Name fields on Person Accounts, Contacts, and Leads are not inline editable. However, their component fields are, such as First Name and Last Name.
Neither the Controlling nor Dependent Picklist fields can be modified through the use of the inline modification on list views.
Filter Logic - You must clean out the filter logic to use Inline Editing. They cannot be used simultaneously. 
If a field is a part of the lookup filter criteria, you will not be able to edit the field.
A field must also be present in at least one-page layout and assign same page layout on users profile in order to inline edit.
Inline editing is not available when the viewer (User) has Accessibility Mode enabled.
The ability to inline edit multiple records at once is also available, but you must have the "Mass Edit from Lists" permission turned on for your user profile. Your System Administrator can verify that your profile has this permission enabled.
We can use "Inline Edit" controlling fields on a List View provided the dependent fields are hidden from the assigned page layout.
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Note: Product list views, you cannot edit multiple records at once. Products can only be inline edited one at a time. If you are unable to find the said permission on the profile, check if "Enhanced Lists" are enabled via setup. (Setup | Customize | User Interface | Enable Enhanced Lists)





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Thanks and Regards
Sandhya