问题
What does it mean in the designer when you add something like saveFileDialog to a form, and it appears in the bottom pane at the bottom of the designer window rather than inside the form like a button would?
回答1:
When something like a SerialPort or SaveFileDialog appears at the bottom the designer, it just means that component is not a physical thing that gets drawn on the form/window. To avoid confusion, it is displayed outside of the window. You can click on it to see and change its properties, but it will not get drawn on the window the same way a button would.
来源：https://stackoverflow.com/questions/30283875/visual-studio-designer-bottom-pane