com.sec.android.app.flashbarservice is simply the "brain" behind your Samsung tablet's multitasking sidebar.

When you swipe from the side of your screen to open a list of apps for split-screen viewing or pop-up windows, this service is what makes that visual interface function. Key Functions

If you see it using battery, it’s usually because you’ve been frequently using split-screen features. If you don't use these features at all, you can turn off "Edge Panels" in your Display Settings , which will put the service into a dormant state.

It is a legitimate Samsung system application. It is not malware, spyware, or a virus. Because it is a system app, you will often see it running in the background so that your multitasking features are ready to use instantly. Can (or should) you disable it?

It manages the "active" state of the sidebar, ensuring it stays hidden until you gesture for it.

Generally, you disable or force-stop this service.

It handles the sidebar that allows you to drag and drop apps into split-screen mode.