Child Controls Inside Panel doesn't resize on Form resize

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C#

WinForms

I want to display banner image on top of MDI form along with some menus. Menus should display on that banner image at right side's bottom position. To achieve this I followed below steps:

1. Added MDI form
2. Panel (pnlHeader) - which backcolor is black to match the image background
3. Picturebox to display banner image and added it inside the pnlHeader
4. Added menustrip (dock = none) in Picturebox as want to display menus on banner image (beside logo)

When I resize the form, picture box image and menustrip doesn't resize even Panel is Dock to Top. Is there any suggestion on this? I cannot provide you code due to security reason.