At this time you may concurrently scan 25 symbols. 

In platforms that support workspaces or chartbooks, this includes the symbols that are in other open workspaces or chartbooks. For example, if you have two workspaces open you can split the limit of 25 between the two of them. 10 in one and 15 in another, or 12 in one and 13 in another, as long as the limit of 25 is not exceeded.

If you exceed the limit of 25 and scan more, they will not show up in the VSA Scan Manager or VSA Smart Center, and your computer may slow down and experience performance issues.

We may increase this limit in a future update, this is something we are researching. For performance reasons currently, we have set the limit to 25.