This is something that’s bothered me about Unity ever since I started using multiple monitors again, but it can be observed running Unity in windowed instead of maximized as well. It’s been around for as long as Unity itself and it’s a real pain. Let me explain:
First, I’ll open Unity and put my profiler on my second window. Then, I’ll load Visual Studio and put it on top of Unity. This is a standard setup and I don’t think anyone could really say it’s that niche a layout.
Next, I’ll click on the Profiler. Because of how Unity handles windowing, this brings the main Unity application into focus, immediately covering up Visual Studio.
Whatever application is open on the same monitor as Unity will be immediately covered as soon as you click on the other window. This makes things like testing and modifying assets especially annoying and is a UX fix that should have been considered ages ago.