Im building a sidebar bar app that shows content of selected folder/s and has note jotting features. That shows when the the mouse is moved to the left(for now) edge of the screen.

I want it to show fully when its defined screen area is free and partially when its not.
e.g if u have a web browser maximised, u might now what it to cover ur browser everytime you mover or mouse to the edge.

I am thinking about using a transparent thin dialog which is set to stay at the bottom of screen, as a sensor that would sent a signal on a mouse event.

is there a better what of doing something like this?