SOLUTION: I did this by adding the theme file groups/single/activity.php to my child theme, and then changing the post-form.php to post-form-groups.php. Then I added activity/post-form-groups.php to my child theme as a blank file.
Now the “home” part of the group still shows all activity for the group (forum posts, document uploads through the Group Documents plugin, etc), but doesn’t have the activity box, so users are funneled into creating a new forum thread or replying to an existing thread instead, which is what I want. Hooray!
I agree with the OP – I tried your fix above – but I am still able to see and post activity in the groups.
just to re-trace my steps – I created in my theme (fishbook) groups/single/activity.php – and pasted the activity.php from /wp-content/plugins/buddypress/bp-themes/bp-default/groups/single/
I then copied wp-content/plugins/buddypress/bp-themes/bp-default/activity/post-form.php to /wp-content/themes/fishbook-buddypress-buddypack/activity/ and renamed it post-form-groups and cleared the contents of that file. However, I still see the activity box etc.
Ah OK – I just edited the activity.php and found post-form.php and replaced it with post-form-groups.php and it worked.
