Hello floele, thanks for the reply. I think it is not needed to create all bitmaps/icons with doubled size. It should be possible to let the used widget just upscale the icons/bitmaps based on the present scaling factor set in Windows. When I look at the GUI of e.g. Paint.NET I see the icons are not created for high resolution, but still have a size that it is possible to use the buttons on high resolution screen as they are upscaled somehow.
If you look at the first screenshot above, scaling already works for the "CDBurner XP" logo, so it is only all the icons on the menu- and toolbar-buttons that appear too small.
(it is not only cosmetic issue but also usability is reduced by this issue. I guess that usage of hires monitors will increase in future, especially on laptops)