Do you mean tasks overlapping between projects?
Maybe using the workload feature will help with this.
Personally I don’t see the need for seeing tasks in timeline as portfolio’s are meant for a high level overview, and I think it is a good nudge to force people that are looking at the portfolio level to view it from the proper altitude.
If the possibility of viewing “all task” is added I think it should default to Milestones.
Hi Jan
Thanks for the response. As mentioned in my reply yesterday, I know there are other ways of viewing tasks - the workload feature perhaps - but as I said in my message yesterday, these are not as clear and intuitive as seeing the timelines laid out in one place. We have explored other views with clients and collaborators we work with on our portfolios of work and they all want to see the timeline tasks in the portfolio view.
As for your conclusion that you don’t personally see the need for seeing tasks in the portfolio timeline that’s fine, but this is not the opinion of our staff, our collaborators or our clients. Nor is it the opinion of the other people that have commented in this topic. I don’t think it would be well received by the people we work with if we told them “they were not looking at things from the proper altitude”
Finally, adding this feature would not change the way you like to view milestones only - you could have a filter set up to have a view that was ‘all tasks’ and a view that was ‘only milestones’. The way it is set up now is restrictive for those of us that want more detail. Surely its better to design these features in such a way that there is flexibility for us all to get the view that we would like to see, no?
Regards
Mark
@Mark_Kelleher sure. I’m just adding another perspective that I think is useful for Asana when evaluating whether to implement this feature or not.
I’m trying to find out what the real problem is, so that’s why I am still curious as to whether you are talking about tasks overlapping between projects or not.
The fact that Asana doesn’t support multiple assignees isn’t well received either. Still I’m glad they don’t. 
Adding my vote in for this as well, and to keep the thread alive 
this is also a major limitation for our teams working across multiple projects. it’s too much to multi home all tasks all the time. need task level detail in portfolio timelines!!
Just signed up a trial and this is disappointing.
Hi all, you may want to have a look at a 3rd-party app instagantt.com (no affiliation) which works great with Asana. You can add multiple projects within the same gantt view, expanding all tasks to view them all in parallel.
You can connect up to 3 projects for free.