For information, i bring on the forum a conversation i had with Michael Gerasimov (who is in charge of the clearcase plugin)
I see many issues with the way changelists work now in relation to activities :
1 - what happens if 2 activities have the same headline in CC but in different views (i've told you about this in my precedent message)
2 - At which level do the changelist currently work ? If you create a changelist in IntelliJ, nothing is done in CC, which is bad from my point of view.
3 - Obsolete & locked activities. How to see them and mark/unmark them obsolete (you seem to have fixed this in 7.x, nice) ?
Here is my proposal, with a small scenario that i came up with :
1 - No changelist, no activity, fresh new project, with moduleA, moduleB, moduleC each in a different UCM view, UCM mode on in IntelliJ.
2 - I want to fix a bug that involves changing files in moduleA and moduleB. Ideally i would like to view this as a single changlist in IntelliJ. But that means 2 CC activities, because moduleA is in a different view than moduleB.
3 - I navigate to a file of moduleA, let's say FileA.java, i type a keystroke, and IntelliJ pops up a dialog asking me how i want to "clear the read-only status", using filesystem or using version control integration. At that point, still no activity has been created in CC. In current IntelliJ version, if you select the latter option (using VCS), you'll get an error message saying that no activity is set in view. I think this is the best time to ask for the creation of a changelist, and at the same time the creation of a CC activity which will be created in the view where FileA.java is located and whose name will be the same as the changelist. (note : it works that way in Ecplise, it pops up the native CC activity creation window).
4 - So i create a new changelist 'Fixed hard to find bug', IntelliJ detects that there is no activity in ModuleA's view and asks me to create one, with the name 'Fixed hard to find bug'.
5 - All right, i've made my fix in FileA.java. Now i want to fix FileB.java which is in moduleB which is in some other view. I have this changelist 'Fixed hard to find bug', but it's associated to an activity in ModuleA. The problem is that i'd like very much to see FileB.java in that changelist, to be able to commit those related changes in one step. You have two design options : either one changelist matches one activity (which means only one view), or one changelist can have many activities associated to it, but in that case you should restrict to the ones that have exactly the same name. Now suppose you choose to do so in IntelliJ, i'll be able to see FileA and FileB both in my changelist, and have 'Fixed hard to find bug' CC activity created in moduleA's view and an activity with the same name in ModuleB's view.
6 - I can now commit my changes. So i choose my changelist and press the 'commit changes' button. The checkout files are now checkin and IntelliJ should propose me to obsolete the underlying CC activities.
Even with this system, i see some issues :
1 - What happens if i mark in CC the activity 'Fixed hard to find bug' in viewA as obsolete, but not the other ?
2 - What if i rename in CC one of the activities ? Intellij should detect that and show 2 changelists with the correct checked out files under each.
3 - If you move files from a changelist to a new activity, you have to create in CC all needed activities.
4 - What happens if you rename changelists (i think you should rename automatically CCactivites)
To conclude, as i see things, in UCM mode, a changelist in IntelliJ is just a mirror of an activity in CC, for base clearcase, that's ok : changelist just are just 'organized' comments.
If you have many CC activities with the same name, group them under a unique changelist. Maybe that should be an option, some people may prefer to have a 1-1 relationship (you could provide a button like 'group identical activities') . As an alternative, create a new concept : group of changelists, just like you came up with group of modules sometimes ago, but it complicated things and it won't make sense probably with regards to other CVS systems.
Hope this helps, don't hesitate to ask me questions, i'm available and i'll be glad to answer.