After months of frustration, I had a ureka moment!
I discovered the reason why — often, THOUGH NOT ALWAYS (!) — nothing would happen when I performed a simple search with 'tag:groceries' and then 'Select/All' and hit 'Share'...
The Goal: I wanted to make sure that 'Jane' had access to all of my tasks with the tag 'groceries'.
_I figured out that in order for your 'Select/All' then 'Share' to work, you actually have to first make sure that none of the tasks that come up in that search are ALREADY SHARED with 'Jane'!
(ie if any of the tasks are shared with 'Jane', the following attempt to share the whole list with her will fail.)
**THUS, to achieve your goal, include in your original search the filter:
(where 'Jane' is the person's rtm username)
This will remove from the group (or Smart List) all of the tasks that have already been shared with 'Jane'.
To recap, your search will actually look like this:
" tag:groceries NOT sharedWith:Jane "
...then simply 'Select/All' and then Share!
In hopes that this saves you hours of frustration!..
Posted at 12:52am on September 27, 2012