In an assembly, I want to drag a selection window on top of a part/face without picking said part that fills the screen. If you pick the first corner of the window do you have to be in 'open space' or is there a filter or keystroke combo that would allow you to pick the first corner of the window wherever you want.
Starting your drag selection in dead space is the only way to get that without using a tool.
If you use the Volume Select, you can get what you want. Start the tool, then draw your window, then you can use the different drag handles to select actual volume of selection.