"Active Items" is a blue vertical box to the left of the screen. The is a technology that allows you work in more than one record at a time, track which record you are in and quickly switch back and forth between records held in the "Active items' box. This is very useful tool.
For example, you can create a new estimate and also be able to look up an invoice if another customer calls without you needing to close the new estimate. You can then look up a work order if a subcontractor walks in on you. So in this example you can be working on three different topics.
The Active Items workspace is similar to Word and Excel where you can continue to work and save, and then you can close an item to completely stop working on it. Our feature protects users from dropped Internet connections or when there are just too many things happening at any given time. You are forced to remember what you are in the middle of until you say you are done.
More Information, including suggested limits can be found on the Multi Tasking help page.