That is not the default Win32 combobox. I don't know what you're using, but it's not the plain c api.

That is the default combobox if you enable "visual styles" (which you should do on Windows XP and above)

binjooou: The whole point for me when using win32 is to use the default look, since it's a better ui compared to todays flat design. But I acknowledge that there could be a little less dpi work associated with enabling visual styles.

The best UI is the UI your users are used to, and 1% of Windows users are used to the Win 2000 gray UI.

Win XP came out 22 years ago.

oblio: Have you seen the other comments for this post? There's plenty of people who think the default win32 gui is awesome.

This is most definitely the default combo box. At this point I'm very confused what you are using.

dataflow: That is indeed a nice looking combobox in your new screenshot. I'm not getting that result on win10 when using the Win32 c api, and if you're not using something like WinForms, MFC or another abstraction, it's hard to say why it works for you. I'm on a 4k resolution with 200% scaling and the button is way too thin.

I'm not sure if this makes a difference but do you see that problem with dialogs (resources + DialogBox) rather than basic windows?

If I remember & get a chance later I can try to make a minimal example.

No, win10