Today I created a C# Winform with a ToolStrip and a SplitContainer beneath it. I wanted the SplitContainer to fill all of the form’s area but should start just under the ToolStrip, just like what you see in a normal Windows Form. To cover all area on the form and resize the SplitContainer with Form resize action I set the Dock property to FILL and the ToolStrip’s Dock property to TOP. The result was a SplitContainer spanning the whole Form and a ToolStrip on top of it. No! I tried a couple of different Dock value combinations with these controls but every time the result was one of them hiding the other one. And if you don’t set the Dock property it won’t resize itself with the Form. After a little research on the internet and trying with different options I figured it out. The solution was not with the Docking values combination, they were right at the very first instance. It is the “Z” order of your controls which matter. Either:
- Right click on SplitContainer and select “Bring to Front”
- Or call BringToFront() in the code
The ToolStrip has to be at the back but since its Dock is set to TOP it will always be shown. And since SplitContainer is now brought at the Front it can’t be hidden by the ToolStrip.

