### .NET version latest .NET 10.0 build ### Did it work in .NET Framework? No ### Did it work in any of the earlier releases of .NET Core or .NET 5+? This is a regression issue, not reproduce .NET 9.0 ### Issue description The combobox refuses dark theme when on first tabpage of a tabcontrol **Expected Results:** <img width="742" height="415" alt="Image" src="https://github.com/user-attachments/assets/f62707dd-8fec-49da-9fcf-6af4dd4bc3c2" /> **Actual Results:** <img width="671" height="405" alt="Image" src="https://github.com/user-attachments/assets/65587d1c-50e1-452b-8c84-3cbbace6ea30" /> ### Steps to reproduce 1. Create a .NET winforms project with a TabCpntrol control 2. Add a Combobox contorl in the tabPage1 3. Set app under Dark mode in program.cs file `Application.SetColorMode(SystemColorMode.Dark);` 4. Run the application **More info:** 1. The issue can reproduce when setting the DropDownStyle as **DropDown/DropDownList**, not reproduce when setting the DropDownStyle as Sample