Should it be possible to check in these changes to same change set ?
Yes you can.
The contextual menu shows a
check in > new change set
check in > (an existing change set name)
Select the second entry, and you will add your modification to the existing change set.
The only case where this option is not available is when you close a change set (right-click / close).
Source: help page:
Expand the Unresolved folder to see its contents.
- To check in the entire set of unresolved changes to the current change set, right-click the
Unresolved
folder and clickCheck-in all
.- To check in an individual item in the Unresolved folder, right-click it, click
Check-in
, and clickan existing change set
to receive the change, or clickNew change set
to create a change set.
(A file or folder in a component cannot be part of more than one active change set.
When a file or folder is included in an active change set, all changes to it become part of that change set whether or not the change set is current, and changes to that file or folder cannot be explicitly checked in to a new change set until the active change set that includes it is completed.)