With all the improvements in SP1 and 19.1, is Pega Robotic Automation now able to control IE with multiple tabs? It was not possible in 2016 and prior, as it was a requirement and recommendation to launch new windows and adapters launch a new window and not additional tabs.
19.1 does not have any changes in the area of IE tabs. If you wish to launch your applications in tabs, then I would suggest using Chrome. In IE, each IE window (the container holding all of the tabs) will be its own adapter, so it would grow larger and larger as you add more tabs within it. In Chrome, once an adapter is started, it will match the page in whatever window or tab that the page launches in. This is because of how IE handles tabs versus Chrome and the hierarchy of the process.