Sadashiv, respectfully, in my experience, whether a column has been formatted in Text Mode (including just "flipping" to it and saving -- an easy test I encourage you to try yourself), its editability is not affected unless the valuefield= is changed to valueexpression=, the latter being a technique I sometimes use to intentionally force a read only result.
Randy, to now sadly dash what little hope I might have just given you, the reason you cannot edit the list of enumerated Tasks on this Project report you are working on is (pardon the circular logic) because it is a list of enumerated Tasks on a Project report.
The Rule for editing data within a grid in Workfront is that only data at the object level upon which the report is based may be edited. So, on a Project report, the Project Name, Owner, Custom Data, etc. can be edited; but (for example) neither the Portfolio Name (pulled down) nor the list of Tasks (pulled up) may be edited.
Regards,
Doug