How to have a border width for a splitter container bar separator in winform?

The splitter container bar separator by default has no width so you can just see an ugly dotted line in the GUI. How to have a width like splitter 开发者_Python百科in Visual Studio ? I can't see any property for this.

The usual approach is to give the panels distinct BackColors so that it is obvious where to place the cursor to start dragging. Another thing you could do is put a Panel on the left side and set its Dock property to Right. Give it a distinct BackColor and set its width to 2.