You could create a custom component, but that would take a long time to get your desired functionality. This is what Salesforce has done. Pretty sure this related list on page layouts isn’t as customizable as most other related lists. Salesforce has done some super flexible related lists where they’ve had to create special objects/visualforce to display them on page layouts. Ie. Contact Roles, Notes & Attachments, & Google Docs, and in this case Tasks and Activities. Hopefully I’m wrong and there’s another easier way, because I’d like to see this functionality as well. Sounds like a new component would be in order. A multi object table component. Probably already an idea in the community.

The problem here is that Salesforce has a sObject call “Activity History” that combines these two objects.  But salesforce does not allow SOQL access to that object.  This means Skuid cannot access it.  We can get to Tasks and Events,  but not the combined object.  I know that Tasks and Events are some of the most highly used objects in Salesforce and so they probably have good reason to put these limits on.  Its the burden we accept to live in this multi-tenant environment.

You can put tasks and events together in a calendar.  That component accepts mutliple objects in separate event sources.

The calendar requires a date time field,  so you would either have to add a custom “due date” field, or build a formula that translated the due date into a date time field. 

Hopefully that explains the situation and gives you some workaround.  Sorry.